Adaptive color transform in video coding

ABSTRACT

A method of video processing, including performing a conversion between a video unit of a video and a bitstream representation of the video, wherein the conversion includes applying a deblocking filter to at least some samples on boundaries of the video unit, wherein deblocking quantization parameter (QP) values used in the deblocking filter are determined according to a rule, and wherein the rule specifies that whether the deblocking QP values are equal to dequantization QP values for the video unit is based on whether an adaptive color transform (ACT) mode is applied to the video unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/US2020/067264, filed on Dec. 29, 2020, which claims the priorityto and benefits of International Patent Application No.PCT/CN2019/130851, filed on Dec. 31, 2019. All the aforementioned patentapplications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This patent document relates to video coding techniques, devices andsystems.

BACKGROUND

Currently, efforts are underway to improve the performance of currentvideo codec technologies to provide better compression ratios or providevideo coding and decoding schemes that allow for lower complexity orparallelized implementations. Industry experts have recently proposedseveral new video coding tools and tests are currently underway fordetermining their effectivity.

SUMMARY

Devices, systems and methods related to digital video coding, andspecifically, to management of motion vectors are described. Thedescribed methods may be applied to existing video coding standards(e.g., High Efficiency Video Coding (HEVC) or Versatile Video Coding)and future video coding standards or video codecs.

In one representative aspect, the disclosed technology may be used toprovide a method for video processing. This method includes performing aconversion between a video unit of a video and a bitstreamrepresentation of the video, where the conversion includes applying adeblocking filter to at least some samples on boundaries of the videounit, where deblocking quantization parameter (QP) values used in thedeblocking filter are determined according to a rule, and where the rulespecifies that whether the deblocking QP values are equal todequantization QP values for the video unit is based on whether anadaptive color transform (ACT) mode is applied to the video unit.

In another representative aspect, the disclosed technology may be usedto provide a method for video processing. This method includesperforming a conversion between a video unit of a video and a bitstreamrepresentation of the video according to a rule, where the rulespecifies that an adaptive color transform (ACT) mode and a block-baseddelta pulse code modulation (BDPCM) coding tool are available for codingthe video unit in a mutually exclusive manner.

In another representative aspect, the disclosed technology may be usedto provide a method for video processing. This method includesdetermining, for a conversion between a video unit of a video and abitstream representation of the video, whether a block differentialpulse code modulation (BDPCM) coding tool is enabled for the video unitbased on whether an adaptive color transform (ACT) mode is enabled forthe video unit; and performing the conversion based on the determining.

In another representative aspect, the disclosed technology may be usedto provide a method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such that whena chroma quantization parameter (QP) table is used to derive parametersof the deblocking filter, processing by the chroma QP table is performedon individual chroma QP values.

In another representative aspect, the disclosed technology may be usedto provide another method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such thatchroma QP offsets are used in the deblocking filter, wherein the chromaQP offsets are at picture/slice/tile/brick/subpicture level.

In another representative aspect, the disclosed technology may be usedto provide another method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such thatchroma QP offsets are used in the deblocking filter, wherein informationpertaining to a same luma coding unit is used in the deblocking filterand for deriving a chroma QP offset.

In another representative aspect, the disclosed technology may be usedto provide another method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such thatchroma QP offsets are used in the deblocking filter, wherein anindication of enabling usage of the chroma QP offsets is signaled in thebitstream representation.

In another representative aspect, the disclosed technology may be usedto provide another method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such thatchroma QP offsets are used in the deblocking filter, wherein the chromaQP offsets used in the deblocking filter are identical of whether JCCRcoding method is applied on a boundary of the video unit or a methoddifferent from the JCCR coding method is applied on the boundary of thevideo unit.

In another representative aspect, the disclosed technology may be usedto provide another method for video processing. This method includesperforming a conversion between a video unit and a bitstreamrepresentation of the video unit, wherein, during the conversion, adeblocking filter is used on boundaries of the video unit such thatchroma QP offsets are used in the deblocking filter, wherein a boundarystrength (BS) of the deblocking filter is calculated without comparingreference pictures and/or a number of motion vectors (MVs) associatedwith the video unit at a P side boundary with reference pictures of thevideo unit at a Q side boundary.

In another example aspect, another method of video processing isdisclosed. The method includes determining, for a conversion between avideo unit of a component of a video and a bitstream representation ofthe video, a size of a quantization group for the video unit, based on aconstraint rule that specifies that the size must be larger than K,where K is a positive number and performing the conversion based on thedetermining.

Further, in a representative aspect, an apparatus in a video systemcomprising a processor and a non-transitory memory with instructionsthereon is disclosed. The instructions upon execution by the processor,cause the processor to implement any one or more of the disclosedmethods.

Additionally, in a representative aspect, a video decoding apparatuscomprising a processor configured to implement any one or more of thedisclosed methods.

In another representative aspect, a video encoding apparatus comprisinga processor configured to implement any one or more of the disclosedmethods.

Also, a computer program product stored on a non-transitory computerreadable media, the computer program product including program code forcarrying out any one or more of the disclosed methods is disclosed.

The above and other aspects and features of the disclosed technology aredescribed in greater detail in the drawings, the description and theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of an overall processing flow of a blockingdeblocking filter process.

FIG. 2 shows an example of a flow diagram of a Bs calculation.

FIG. 3 shows an example of a referred information for Bs calculation atCTU boundary.

FIG. 4 shows an example of pixels involved in filter on/off decision andstrong/weak filter selection.

FIG. 5 shows an example of an overall processing flow of deblockingfilter process in VVC.

FIG. 6 shows an example of a luma deblocking filter process in VVC.

FIG. 7 shows an example of a chroma deblocking filter process in VVC

FIG. 8 shows an example of a filter length determination for sub PUboundaries.

FIGS. 9A and 9B show examples of center positions of a chroma block.

FIG. 10 shows examples of blocks at P side and Q side.

FIG. 11 shows examples of usage of a luma block's decoded information.

FIG. 12 is a block diagram of an example of a hardware platform forimplementing a visual media decoding or a visual media encodingtechnique described in the present document.

FIG. 13 shows a flowchart of an example method for video coding.

FIG. 14A shows an example of Placement of CC-ALF with respect to otherloop filters.

FIG. 14B shows an example of Placement of CC-ALF with respect to adiamond shaped filter.

FIG. 15 shows an example flowchart for an adaptive color transform (ACT)process.

FIG. 16 shows an example flowchart for high-level deblocking controlmechanism.

FIG. 17 shows an example flowchart for high-level deblocking controlmechanism.

FIG. 18 is a block diagram that illustrates a video coding system inaccordance with some embodiments of the present disclosure.

FIG. 19 is a block diagram that illustrates an encoder in accordancewith some embodiments of the present disclosure.

FIG. 20 is a block diagram that illustrates a decoder in accordance withsome embodiments of the present disclosure.

FIG. 21 is a block diagram of an example video processing system inwhich disclosed techniques may be implemented.

FIGS. 22-24 are flowcharts for example methods of video processing.

DETAILED DESCRIPTION 1. Video Coding in HEVC/H.265

Video coding standards have evolved primarily through the development ofthe well-known ITU-T and ISO/IEC standards. The ITU-T produced H.261 andH.263, ISO/IEC produced MPEG-1 and MPEG-4 Visual, and the twoorganizations jointly produced the H.262/MPEG-2 Video and H.264/MPEG-4Advanced Video Coding (AVC) and H.265/HEVC standards. Since H.262, thevideo coding standards are based on the hybrid video coding structurewherein temporal prediction plus transform coding are utilized. Toexplore the future video coding technologies beyond HEVC, Joint VideoExploration Team (JVET) was founded by VCEG and MPEG jointly in 2015.Since then, many new methods have been adopted by JVET and put into thereference software named Joint Exploration Model (JEM). In April 2018,the Joint Video Expert Team (JVET) between VCEG (Q6/16) and ISO/IEC JTC1SC29/WG11 (MPEG) was created to work on the VVC standard targeting at50% bitrate reduction compared to HEVC.

The latest version of VVC draft, i.e., Versatile Video Coding (Draft 6)could be found at:http://phenix.it-sudparis.eu/jvet/doc_end_user/documents/15_Gothenburg/wg11/JVET-02001-v14.zip.The latest reference software of VVC, named VTM, could be found at:https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/tags/VTM-6.0.

2.1. Deblocking Scheme in HEVC

A deblocking filter process is performed for each CU in the same orderas the decoding process. First, vertical edges are filtered (horizontalfiltering), then horizontal edges are filtered (vertical filtering).Filtering is applied to 8×8 block boundaries which are determined to befiltered, for both luma and chroma components. 4×4 block boundaries arenot processed in order to reduce the complexity.

FIG. 1 illustrates the overall processing flow of deblocking filterprocess. A boundary can have three filtering status: no filtering, weakfiltering and strong filtering. Each filtering decision is based onboundary strength, Bs, and threshold values, β and t_(C).

Three kinds of boundaries may be involved in the filtering process: CUboundary, TU boundary and PU boundary. CU boundaries, which are outeredges of CU, are always involved in the filtering since CU boundariesare always also TU boundary or PU boundary. When PU shape is 2N×N (N>4)and RQT depth is equal to 1, TU boundary at 8×8 block grid and PUboundary between each PU inside CU are involved in the filtering. Oneexception is that when the PU boundary is inside the TU, the boundary isnot filtered.

2.1.1. Boundary Strength Calculation

Generally speaking, boundary strength (Bs) reflects how strong filteringis needed for the boundary. If Bs is large, strong filtering should beconsidered.

Let P and Q be defined as blocks which are involved in the filtering,where P represents the block located in left (vertical edge case) orabove (horizontal edge case) side of the boundary and Q represents theblock located in right (vertical edge case) or above (horizontal edgecase) side of the boundary. FIG. 2 illustrates how the Bs value iscalculated based on the intra coding mode, existence of non-zerotransform coefficients and motion information, reference picture, numberof motion vectors and motion vector difference.

Bs is calculated on a 4×4 block basis, but it is re-mapped to an 8×8grid. The maximum of the two values of Bs which correspond to 8 pixelsconsisting of a line in the 4×4 grid is selected as the Bs forboundaries in the 8×8 grid.

In order to reduce line buffer memory requirement, only for CTUboundary, information in every second block (4×4 grid) in left or aboveside is re-used as depicted in FIG. 3 .

2.1.2. β and tC Decision

Threshold values β and t_(C) which involving in filter on/off decision,strong and weak filter selection and weak filtering process are derivedbased on luma quantization parameter of P and Q blocks, QP_(P) andQP_(Q), respectively. Q used to derive β and t_(C) is calculated asfollows.Q=((QP_(P)+QP_(Q)+1)>>1).

A variable β is derived as shown in Table 1, based on Q. If Bs isgreater than 1, the variable t_(C) is specified as Table 1 with Clip3(0,55, Q+2) as input. Otherwise (BS is equal or less than 1), the variablet_(C) is specified as Table 1 with Q as input.

TABLE 1 Derivation of threshold variables β and t_(C) from input Q Q 0 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 β 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 6 7 8 t_(C) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Q 19 20 21 22 2324 25 26 27 28 29 30 31 32 33 34 35 36 37 β 9 10 11 12 13 14 15 16 17 1820 22 24 26 28 30 32 34 36 t_(C) 1 1 1 1 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 Q38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 β 38 40 42 44 4648 50 52 54 56 58 60 62 64 64 64 64 64 t_(C) 5 5 6 6 7 8 9 9 10 10 11 1112 12 13 13 14 142.1.3. Filter on/Off Decision for 4 Lines

Filter on/off decision is done for four lines as a unit. FIG. 4illustrates the pixels involving in filter on/off decision. The 6 pixelsin the two red boxes for the first four lines are used to determinefilter on/off for 4 lines. The 6 pixels in two red boxes for the second4 lines are used to determine filter on/off for the second four lines.

If dp0+dq0+dp3+dq3<β, filtering for the first four lines is turned onand strong/weak filter selection process is applied. Each variable isderived as follows.

dp0 = ❘p_(2, 0) − 2 * p_(1, 0) + p_(0, 0)❘, dp3 = ❘p_(2, 3) − 2 * p_(1, 3) + p_(0, 3)❘, dp4 = ❘p_(2, 4) − 2 * p_(1, 4) + p_(0, 4)❘, dp7 = ❘p_(2, 7) − 2 * p_(1, 7) + p_(0, 7)❘dq0 = ❘q_(2, 0) − 2 * q_(1, 0) + q_(0, 0)❘, dq3 = ❘q_(2, 3) − 2 * q_(1, 3) + q_(0, 3)❘, dq4 = ❘q_(2, 4) − 2 * q_(1, 4) + q_(0, 4)❘, dq7 = ❘q_(2, 7) − 2 * q_(1, 7) + q_(0, 7)❘

If the condition is not met, no filtering is done for the first 4 lines.Additionally, if the condition is met, dE, dEp1 and dEp2 are derived forweak filtering process. The variable dE is set equal to 1. Ifdp0+dp3<(β+(β>>1))>>3, the variable dEp1 is set equal to 1. Ifdq0+dq3<(β+(β>>1))>>3, the variable dEq1 is set equal to 1.

For the second four lines, decision is made in a same fashion withabove.

2.1.4. Strong/Weak Filter Selection for 4 Lines

After the first four lines are determined to filtering on in filteron/off decision, if following two conditions are met, strong filter isused for filtering of the first four lines. Otherwise, weak filter isused for filtering. Involving pixels are same with those used for filteron/off decision as depicted in FIG. 4 .1)2*(dp0+dq0)<(β>>2),|p3₀ −p0₀ |+|q0₀ −q3₀|<(β>>3) and |p0₀ −q0₀|<(5*t_(C)+1)>>12)2*(dp3+dq3)<(β>>2),|p3₃ −p0₃ |+|q0₃ −q3₃|<(β>>3) and |p0₃ −q0₃|<(5*t_(C)+1)>>1

As a same fashion, if following two conditions are met, strong filter isused for filtering of the second 4 lines. Otherwise, weak filter is usedfor filtering.1)2*(dp4+dq4)<(β>>2),|p3₄ −p0₄ |+|q0₄ −q3₄|<(β>>3) and |p0₄ −q0₄|<(5*t_(C)+1)>>12)2*(dp7+dq7)<(β>>2),|p3₇ −p0₇ |+|q0₇ −q3₇|<(β>>3) and |p0₇ −q0₇|<(5*t_(C)+1)>>12.1.4.1. Strong Filtering

For strong filtering, filtered pixel values are obtained by followingequations. It is worth to note that three pixels are modified using fourpixels as an input for each P and Q block, respectively.p ₀′=(p ₂+2*p ₁+2*p ₀+2*q ₀ +q ₁+4)>>3q ₀′=(p ₁+2*p ₀+2*q ₀+2*q ₁ +q ₂+4)>>3p ₁′=(p ₂ +p ₁ +p ₀ +q ₀+2)>>2q ₁′=(p ₀ +q ₀ +q ₁ +q ₂+2)>>2p ₂′=(2*p ₃+3*p ₂ +p ₁ +p ₀ +q ₀+4)>>3q ₂′=(p ₀ +q ₀ +q ₁+3*q ₂+2*q ₃+4)>>32.1.4.2. Weak Filtering

Let's define Δ as follows.Δ=(9*(q ₀ −p ₀)−3*(q ₁ −p ₁)+8)>>4When abs(Δ) is less than t_(C)*10,Δ=Clip3(−t _(C) ,t _(C),Δ)p ₀′=Clip1_(Y)(p ₀+Δ)q ₀′=Clip1_(Y)(q ₀−Δ)If dEp1 is equal to 1,Δp=Clip3(−(t _(C)>>1),t _(C)>>1,(((p ₂ +p ₀+1)>>1)−p ₁+Δ)>>1)p ₁′=Clip1_(Y)(p ₁ +Δp)If dEq1 is equal to 1,Δq=Clip3(−(t _(C)>>1),t _(C)>>1,(((q ₂ +q ₀+1)>>1)−q ₁−Δ)>>1)q ₁′=Clip1_(Y)(q ₁ +Δq)

It is worth to note that maximum two pixels are modified using threepixels as an input for each P and Q block, respectively.

2.1.4.3. Chroma Filtering

Bs of chroma filtering is inherited from luma. If Bs>1 or if codedchroma coefficient existing case, chroma filtering is performed. Noother filtering decision is there. And only one filter is applied forchroma. No filter selection process for chroma is used. The filteredsample values p₀′ and q₀′ are derived as follows.Δ=Clip3(−t _(C) ,t _(C),(((((q ₀ −p ₀)<<2)+p ₁ −q ₁+4)>>3))p ₀′=Clip1_(C)(p ₀+Δ)q ₀′=Clip1_(C)(q ₀−Δ)

2.2 Deblocking Scheme in VVC

In the VTM6, deblocking filtering process is mostly the same to those inHEVC. However, the following modifications are added.

-   -   a) The filter strength of the deblocking filter dependent of the        averaged luma level of the reconstructed samples.    -   b) Deblocking tC table extension and adaptation to 10-bit video    -   c) 4×4 grid deblocking for luma    -   d) Stronger deblocking filter for luma    -   e) Stronger deblocking filter for chroma    -   f) Deblocking filter for subblock boundary    -   g) Deblocking decision adapted to smaller difference in motion

FIG. 5 depicts a flowchart of deblocking filters process in VVC for acoding unit.

2.2.1. Filter Strength Dependent on Reconstructed Average Luma

In HEVC, the filter strength of the deblocking filter is controlled bythe variables β and t_(C) which are derived from the averagedquantization parameters qP_(L). In the VTM6, deblocking filter controlsthe strength of the deblocking filter by adding offset to qP_(L)according to the luma level of the reconstructed samples if the SPS flagof this method is true. The reconstructed luma level LL is derived asfollow:LL=((p _(0,0) +p _(0,3) +q _(0,0) +q _(0,3))>>2)/(1<<bitDepth)  (3-1)where, the sample values p_(i,k) and q_(i,k) with i=0 . . . 3 and k=0and 3 are derived as shown in Section 2. Then LL is used to decide theoffset qpOffset based on the threshold signaled in SPS. After that, theqP_(L), which is derived as follows, is employed to derive the β andt_(C).qP_(L)=((Qp_(Q)+Qp_(P)+1)>>1)+qpOffset  (3-2)where Qp_(Q) and Qp_(P) denote the quantization parameters of the codingunits containing the sample q_(0,0) and p_(0,0), respectively. In thecurrent VVC, this method is only applied on the luma deblocking process.2.2.2. 4×4 Deblocking Grid for Luma

HEVC uses an 8×8 deblocking grid for both luma and chroma. In VTM6,deblocking on a 4×4 grid for luma boundaries was introduced to handleblocking artifacts from rectangular transform shapes. Parallel friendlyluma deblocking on a 4×4 grid is achieved by restricting the number ofsamples to be deblocked to 1 sample on each side of a vertical lumaboundary where one side has a width of 4 or less or to 1 sample on eachside of a horizontal luma boundary where one side has a height of 4 orless.

2.2.3. Boundary Strength Derivation for Luma

The detailed boundary strength derivation could be found in Table 2. Theconditions in Table 2 are checked sequentially.

TABLE 2 Boundary strength derivation Conditions Y U V P and Q are BDPCM0 N/A N/A P or Q is intra 2 2 2 It is a transform block edge, and P or Qis CIIP 2 2 2 It is a transform block edge, and P or Q has non-zerotransform coefficients 1 1 1 It is a transform block edge, and P or Q isJCCR N/A 1 1 P and Q are in different coding modes 1 1 1 One or more ofthe following conditions are true: 1 N/A N/A 1. P and Q are both IBC,and the BV distance >= half-pel in x- or y-di 2. P and Q have differentref pictures*, or have different number of MVs 3. Both P and Q have onlyone mv, and the MV distance >= half -pel in x- or y-dir 4. P has two MVspointing to two different ref pictures, and P and Q have same refpictures in the list 0, the MV pair in the list 0 or list 1 has adistance >= half-pel in x- or y-dir 5. P has two MVs pointing to twodifferent ref pictures, and P and Q have different ref pictures in thelist 0, the MV of P in the list 0 and the MV of Q in the list 1 have thedistance >= half-pel in x- or y-dir, or the MV of Pin the list 1 and theMV of Q in the list 0 have the distance >= half-pel in x- or y-dir 6.Both P and Q have two MVs pointing to the same ref pictures, and both ofthe following two conditions are satisfied: The MV of P in the list 0and the MV of Q in the list 0 has a distance >= half-pel in x- or y-diror the MV of P in the list 1 and the MV of Q in the list 1 has adistance >= half-pel in x- or y-dir The MV of P in the list 0 and the MVof Q in the list 1 has a distance >= half-pel in x- or y-dir or the MVof P in the list 1 and the MV of Q in the list 0 has a distance >=half-pel in x- or y-dir *Note: The determination of whether thereference pictures used for the two coding sublocks are the same ordifferent is based only on which pictures are referenced, without regardto whether a prediction is formed using an index into reference picturelist 0 or an index into reference picture list 1, and also withoutregard to whether the index position within a reference picture list isdifferent. Otherwise 0 0 02.2.4. Stronger Deblocking Filter for Luma

The proposal uses a bilinear filter when samples at either one side of aboundary belong to a large block. A sample belonging to a large block isdefined as when the width>=32 for a vertical edge, and when height>=32for a horizontal edge.

The bilinear filter is listed below.

Block boundary samples pi for i=0 to Sp-1 and qi for j=0 to Sq−1 (pi andqi follow the definitions in HEVC deblocking described above) are thenreplaced by linear interpolation as follows:p _(i)′=(f _(i)*Middle_(s,t)+(64−f _(i))*P _(s)+32)>>6),clipped to p_(i)±tcPD_(i)q _(j)′=(g _(j)*Middle_(s,t)+(64−g _(j))*Q _(s)+32)>>6),clipped to q_(j)±tcPD_(j)where tcPD_(i) and tcPD_(j) term is a position dependent clippingdescribed in Section 2.2.5 and g_(j), f_(i), Middle_(s,t), P_(s) andQ_(s) are given below:

Sp, Sq f_(i) = 59 − i * 9, can also be described as f = {59, 50, 41, 32,23, 14, 5} 7, 7 g_(j) = 59 − j * 9, can also be described as g = {59,50, 41, 32, 23, 14, 5} (p side: 7, Middle_(7, 7) = (2 * (p_(o) +q_(o)) + p₁ + q₁ + p₂ + q₂ + p₃ + q₃ + p₄ + q side: 7) q₄ + p₅ + q₅ +p₆ + q₆ + 8) >> 4 P₇ = (p₆ + p₇ + 1) >> 1, Q₇ = (q₆ + q₇ + 1) >> 1 7, 3f_(i) = 59 − i * 9, can also be described as f = {59, 50, 41, 32, 23,14, 5} (p side: 7 g_(j) = 53 − j * 21, can also be described as g = {53,32, 11} q side: 3) Middle_(7, 3) = (2 * (p_(o) + q_(o)) + q₀ + 2 * (q₁ +q₂) + p₁ + q₁ + p₂ + p₃ + p₄ + p₅ + p₆ + 8) >> 4 P₇ = (p₆ + p₇ + 1) >>1, Q₃ = (q₂ + q₃ + 1) >> 1 3, 7 g_(j) = 59 − j * 9, can also bedescribed as g = {59, 50, 41, 32, 23, 14, 5} (p side: 3 f_(i) = 53 − i *21, can also be described as f = {53, 32, 11} q side: 7) Middle_(3.7) =(2 * (q_(o) + p_(o)) + p₀ + 2 * (p₁ + p₂) + q₁ + p₁ + q₂ + q₃ + q₄ +q₅ + q₆ + 8) >> 4 Q₇ = (q₆ + q₇ + 1) >> 1, P₃ = (p₂ + p₃ + 1) >> 1 7, 5g_(j) = 58 − j * 13, can also be described as g = {58, 45, 32, 19, 6} (pside: 7 f_(i) = 59 − i * 9, can also be described as f = {59, 50, 41,32, 23, 14, 5} q side: 5) Middle7, 5 = (2 * (p_(o) + q_(o) + p₁ + q₁) +q₂ + p₂ + q₃ + p₃ + q₄ + p₄ + q₅ + p₅ + 8) >> 4 Q₅ = (q₄ + q₅ + 1) >> 1,P₇ = (p₆ + p₇ + 1) >> 1 5, 7 g_(j) = 59 − j * 9, can also be describedas g = {59, 50, 41, 32, 23, 14, 5} (p side: 5 f_(i) = 58 − i * 13, canalso be described as f = {58, 45, 32, 19, 6} q side: 7) Middle5, 7 =(2 * (q_(o) + p_(o) + p₁ + q₁) + q₂ + p₂ + q₃ + p₃ + q₄ + p₄ + q₅ + p₅ +8) >> 4 Q₇ = (q₆ + q₇ + 1) >> 1, P₅ = (p₄ + p₅ + 1) >> 1 5, 5 g_(j) = 58− j * 13, can also be described as g = {58, 45, 32, 19, 6} (p side: 5f_(i) = 58 − i * 13, can also be described as f = {58, 45, 32, 19, 6} qside: 5) Middle5, 5 = (2 * (q_(o) + p_(o) + p₁ + q₁ + q₂ + p₂) + q₃ +p₃ + q₄ + p₄ + 8) >> 4 Q₅ = (q₄ + q₅ + 1) >> 1, P₅ = (p₄ + p₅ + 1) >> 15, 3 g_(j) = 53 − j * 21, can also be described as g = {53, 32, 11} (pside: 5 f_(i) = 58 − i * 13, can also be described as f = {58, 45, 32,19, 6} q side: 3) Middle5, 3 = (q_(o) + p_(o) + p₁ + q₁ + q₂ + p₂ + q₃ +p₃ + 4) >> 3 Q₃ = (q₂ + q₃ + 1) >> 1, P₅ = (p₄ + p₅ + 1) >> 1 3, 5 g_(j)= 58 − j * 13, can also be described as g = {58, 45, 32, 19, 6} (p side:3 f_(i) = 53 − i * 21, can also be described as f = {53, 32, 11} q side:5) Middle3, 5 = (q_(o) + p_(o) + p₁ + q₁ + q₂ + p₂ + q₃ + p₃ + 4) >> 3Q₅ = (q₄ + q₅ + 1) >> 1, P₃ = (p₂ + p₃ + 1) >> 12.2.5. Deblocking Control for Luma

The deblocking decision process is described in this sub-section.

Wider-stronger luma filter is filters are used only if all of theCondition 1, Condition 2 and Condition 3 are TRUE.

The condition 1 is the “large block condition”. This condition detectswhether the samples at P-side and Q-side belong to large blocks, whichare represented by the variable bSidePisLargeBlk and bSideQisLargeBlkrespectively. The bSidePisLargeBlk and bSideQisLargeBlk are defined asfollows.

-   -   bSidePisLargeBlk=((edge type is vertical and p₀ belongs to CU        with width>=32)∥(edge type is horizontal and p₀ belongs to CU        with height>=32))? TRUE:FALSE    -   bSideQisLargeBlk=((edge type is vertical and q₀ belongs to CU        with width>=32)∥(edge type is horizontal and q₀ belongs to CU        with height>=32))? TRUE:FALSE

Based on bSidePisLargeBlk and bSideQisLargeBlk, the condition 1 isdefined as follows. Condition 1=(bSidePisLargeBlk∥bSidePisLargeBlk)?TRUE:FALSE

Next, if Condition 1 is true, the condition 2 will be further checked.First, the following variables are derived:

dp0, dp3, dq0, dq3 are first derived as in HEVC

if (p side is greater than or equal to 32)dp0=(dp0+Abs(p _(5,0)−2*p _(4,0) +p _(3,0))+1)>>1dp3=(dp3+Abs(p _(5,3)−2*p _(4,3) +p _(3,3))+1)>>1if (q side is greater than or equal to 32)dq0=(dq0+Abs(q _(5,0)−2*q _(4,0) +q _(3,0))+1)>>1dq3=(dq3+Abs(q _(5,3)−2*q _(4,3) +q _(3,3))+1)>>1dpq0, dpq3, dp, dq, d are then derived as in HEVC.

Then the condition 2 is defined as follows.

Condition 2=(d<β)? TRUE:FALSE

Where d=dp0+dq0+dp3+dq3, as shown in section 2.1.4.

If Condition 1 and Condition 2 are valid it is checked if any of theblocks uses sub-blocks:

If(bSidePisLargeBlk) If(mode block P == SUBBLOCKMODE)    Sp =5 else   Sp =7 else  Sp = 3 If(bSideQisLargeBlk)   If(mode block Q ==SUBBLOCKMODE)     Sq =5   else     Sq =7 else   Sq = 3

Finally, if both the Condition 1 and Condition 2 are valid, the proposeddeblocking method will check the condition 3 (the large block Strongfilter condition), which is defined as follows.

In the Condition 3 StrongFilterCondition, the following variables arederived:

dpq is derived as in HEVC. sp3 = Abs(p3 − p0 ), derived as in HEVC if (pside is greater than or equal to 32)    if(Sp==5)     sp3 = ( sp3 + Abs(p5 − p3 ) + 1) >> 1    else     sp3 = ( sp3 + Abs( p7 − p3 ) + 1) >> 1sq3 = Abs( q0 − q3 ), derived as in HEVC if (q side is greater than orequal to 32)  If(Sq==5)    sq3 = ( sq3 + Abs( q5 − q3 ) + 1) >> 1   else   sq3 = ( sq3 + Abs( q7 − q3 ) + 1) >> 1

As in HEVC derive, StrongFilterCondition=(dpq is less than (β>>2),sp3+sq3 is less than (3*β>>5), and Abs(p0-q0) is less than (5*tC+1)>>1)?TRUE:FALSE

FIG. 6 depicts the flowchart of luma deblocking filter process.

2.2.6. Strong Deblocking Filter for Chroma

The following strong deblocking filter for chroma is defined:p ₂′=(3*p ₃+2*p ₂ +p ₁ +p ₀ +q ₀+4)>>3p ₁′=(2*p ₃ +p ₂+2*p ₁ +p ₀ +q ₀ +q ₁+4)>>3p ₀′=(p ₃ +p ₂ +p ₁+2*p ₀ +q ₀ +q ₁ +q ₂+4)>>3

The proposed chroma filter performs deblocking on a 4×4 chroma samplegrid.

2.2.7. Deblocking Control for Chroma

The above chroma filter performs deblocking on a 8×8 chroma sample grid.The chroma strong filters are used on both sides of the block boundary.Here, the chroma filter is selected when both sides of the chroma edgeare greater than or equal to 8 (in unit of chroma sample), and thefollowing decision with three conditions are satisfied. The first one isfor decision of boundary strength as well as large block. The second andthird one are basically the same as for HEVC luma decision, which areon/off decision and strong filter decision, respectively.

FIG. 7 depicts the flowchart of chroma deblocking filter process.

2.2.8. Position Dependent Clipping

The proposal also introduces a position dependent clipping tcPD which isapplied to the output samples of the luma filtering process involvingstrong and long filters that are modifying 7, 5 and 3 samples at theboundary. Assuming quantization error distribution, it is proposed toincrease clipping value for samples which are expected to have higherquantization noise, thus expected to have higher deviation of thereconstructed sample value from the true sample value.

For each P or Q boundary filtered with proposed asymmetrical filter,depending on the result of decision making process described in Section2.2, position dependent threshold table is selected from Tc7 and Tc3tables that are provided to decoder as a side information:Tc7={6,5,4,3,2,1,1};Tc3={6,4,2};tcPD=(SP==3)?Tc3:Tc7;tCQD=(SQ==3)?Tc3:Tc7;

For the P or Q boundaries being filtered with a short symmetricalfilter, position dependent threshold of lower magnitude is applied:Tc3={3,2,1});

Following defining the threshold, filtered p′_(i) and q′_(i) samplevalues are clipped according to tCP and tCQ clipping values:p″ _(i)=clip3(p′ _(i) +tcP _(i) ,p′ _(i) −tcP _(i) ,p′ _(i));q″ _(j)=clip3(q′ _(j) +tcQ _(j) ,q′ _(j) −tcQ _(j) ,q′ _(j));where p′_(i) and q′_(i) are filtered sample values, p″_(i) and q′_(j)are output sample value after the clipping and tcP_(i) tcP_(i) areclipping thresholds that are derived from the VVC tc parameter and tcPDand tcQD. Term clip3 is a clipping function as it is specified in VVC.2.2.9. Sub-Block Deblocking Adjustment

To enable parallel friendly deblocking using both long filters andsub-block deblocking the long filters is restricted to modify at most 5samples on a side that uses sub-block deblocking (AFFINE or ATMVP) asshown in the luma control for long filters. Additionally, the sub-blockdeblocking is adjusted such that that sub-block boundaries on an 8×8grid that are close to a CU or an implicit TU boundary is restricted tomodify at most two samples on each side.

Following applies to sub-block boundaries that not are aligned with theCU boundary.

If(mode block Q == SUBBLOCKMODE && edge!=0){  if (!(implicitTU && (edge== (64 / 4))))   if (edge == 2 ∥ edge == (orthogonalLength − 2) ∥ edge== (56 / 4) ∥ edge == (72 / 4))     Sp = Sq = 2;    else     Sp = Sq =3;  else    Sp = Sq = bSideQisLargeBlk? 5:3 }

Where edge equal to 0 corresponds to CU boundary, edge equal to 2 orequal to orthogonalLength-2 corresponds to sub-block boundary 8 samplesfrom a CU boundary etc. Where implicit TU is true if implicit split ofTU is used. FIG. 8 show the flowcharts of determination process for TUboundaries and sub-PU boundaries.

Filtering of horizontal boundary is limiting Sp=3 for luma, Sp=1 andSq=1 for chroma, when the horizontal boundary is aligned with the CTUboundary.

2.2.10. Deblocking Decision Adapted to Smaller Difference in Motion

HEVC enables deblocking of a prediction unit boundary when thedifference in at least one motion vector component between blocks onrespective side of the boundary is equal to or larger than a thresholdof 1 sample. In VTM6, a threshold of a half luma sample is introduced toalso enable removal of blocking artifacts originating from boundariesbetween inter prediction units that have a small difference in motionvectors.

2.3. Combined Inter and Intra Prediction (CIIP)

In VTM6, when a CU is coded in merge mode, if the CU contains at least64 luma samples (that is, CU width times CU height is equal to or largerthan 64), and if both CU width and CU height are less than 128 lumasamples, an additional flag is signalled to indicate if the combinedinter/intra prediction (CIIP) mode is applied to the current CU. As itsname indicates, the CIIP prediction combines an inter prediction signalwith an intra prediction signal. The inter prediction signal in the CIIPmode P_(inter) is derived using the same inter prediction processapplied to regular merge mode; and the intra prediction signal P_(intra)is derived following the regular intra prediction process with theplanar mode. Then, the intra and inter prediction signals are combinedusing weighted averaging where the weight value is calculated dependingon the coding modes of the top and left neighbouring blocks as follows:

-   -   If the top neighbor is available and intra coded, then set        isIntraTop to 1, otherwise set isIntraTop to 0;    -   If the left neighbor is available and intra coded, then set        isIntraLeft to 1, otherwise set isIntraLeft to 0;    -   If (isIntraLeft+isIntraLeft) is equal to 2, then wt is set to 3;    -   Otherwise, if (isIntraLeft+isIntraLeft) is equal to 1, then wt        is set to 2;    -   Otherwise, set wt to 1.

The CIIP prediction is formed as follows:P _(CIIP)=((4−wt)*P _(inter) +wt*P _(intra)+2)>>2

2.4. Chroma QP Table Design in VTM-6.0

A chroma QP table design presented in JVET-O0650 was adopted into VVC.It proposes a signalling mechanism for chroma QP tables, which enablesthat it is flexible to provide encoders the opportunity to optimize thetable for SDR and HDR content. It supports for signalling the tablesseparately for Cb and Cr components. The proposed mechanism signals thechroma QP table as a piece-wise linear function.

2.5. Transform Skip (TS)

As in HEVC, the residual of a block can be coded with transform skipmode. To avoid the redundancy of syntax coding, the transform skip flagis not signalled when the CU level MTS_CU_flag is not equal to zero. Theblock size limitation for transform skip is the same to that for MTS inJEM4, which indicate that transform skip is applicable for a CU whenboth block width and height are equal to or less than 32. Note thatimplicit MTS transform is set to DCT2 when LFNST or MIP is activated forthe current CU. Also the implicit MTS can be still enabled when MTS isenabled for inter coded blocks.

In addition, for transform skip block, minimum allowed QuantizationParameter (QP) is defined as 6*(internalBitDepth−inputBitDepth)+4.

2.6. Joint Coding of Chroma Residuals (JCCR)

VVC Draft 6 supports a mode where the chroma residuals are codedjointly. The usage (activation) of a joint chroma coding mode isindicated by a TU-level flag tu_joint_cbcr_residual_flag and theselected mode is implicitly indicated by the chroma CBFs. The flagtu_joint_cbcr_residual_flag is present if either or both chroma CBFs fora TU are equal to 1. In the PPS and slice header, chroma QP offsetvalues are signalled for the joint chroma residual coding mode todifferentiate from the usual chroma QP offset values signalled forregular chroma residual coding mode. These chroma QP offset values areused to derive the chroma QP values for those blocks coded using thejoint chroma residual coding mode. When a corresponding joint chromacoding mode (modes 2 in Table 3) is active in a TU, this chroma QPoffset is added to the applied luma-derived chroma QP duringquantization and decoding of that TU. For the other modes (modes 1 and 3in Table 3), the chroma QPs are derived in the same way as forconventional Cb or Cr blocks. The reconstruction process of the chromaresiduals (resCb and resCr) from the transmitted transform blocks isdepicted in Table 3. When this mode is activated, one single jointchroma residual block (resJointC[x][y] in Table 3) is signalled, andresidual block for Cb (resCb) and residual block for Cr (resCr) arederived considering information such as tu_cbf_cb, tu_cbf_cr, and CSign,which is a sign value specified in the slice header.

At the encoder side, the joint chroma components are derived asexplained in the following Depending on the mode (listed in the tablesabove), resJointC{1,2} are generated by the encoder as follows:

-   -   If mode is equal to 2 (single residual with reconstruction Cb=C,        Cr=CSign*C), the joint residual is determined according to        resJointC[x][y]=(resCb[x][y]+CSign*resCr[x][y])/2.    -   Otherwise, if mode is equal to 1 (single residual with        reconstruction Cb=C, Cr=(CSign*C)/2), the joint residual is        determined according to        resJointC[x][y]=(4*resCb[x][y]+2*CSign*resCr[x][y])/5.    -   Otherwise (mode is equal to 3, i. e., single residual,        reconstruction Cr=C, Cb=(CSign*C)/2), the joint residual is        determined according to        resJointC[x][y]=(4*resCr[x][y]+2*CSign*resCb[x][y])/5.

TABLE 3 Reconstruction of chroma residuals. The value CSign is a signvalue (+1 or −1), which is specified in the slice header, resJointC[ ][] is the transmitted residual. tu_cbf_cb tu_cbf_cr reconstruction of Cband Cr residuals mode 1 0 resCb[ x ][ y ] = resJointC[ x ][ y ] 1 resCr[x ][ y ] = ( CSign * resJointC[ x ][ y ] ) >> 1 1 1 resCb[ x ][ y ] =resJointC[ x ][ y ] 2 resCr[ x ][ y ] = CSign * resJointC[ x ][ y ] 0 1resCb[ x ][ y ] = 3 ( CSign * resJointC[ x ][ y ] ) >> 1 resCr[ x ][ y ]= resJointC[ x ][ y ]

Different QPs are utilized are the above three modes. For mode 2, the QPoffset signaled in PPS for JCCR coded block is applied, while for othertwo modes, it is not applied, instead, the QP offset signaled in PPS fornon-JCCR coded block is applied.

The corresponding specification is as follows:

8.7.1 Derivation Process for Quantization Parameters

The variable Qp_(Y) is derived as follows:Qp_(Y)=((qP_(Y_PRED)+CuQpDeltaVal+64+2*QpBdOffset_(Y))%(64+QpBdOffset_(Y)))−QpBdOffset_(Y)  (8-933)The luma quantization parameter Qp′_(Y) is derived as follows:Qp′_(Y)=Qp_(Y)+QpBdOffset_(Y)  (8-934)When ChromaArrayType is not equal to 0 and treeType is equal toSINGLE_TREE or DUAL_TREE_CHROMA, the following applies:

-   -   When treeType is equal to DUAL_TREE_CHROMA, the variable Qp_(Y)        is set equal to the luma quantization parameter Qp_(Y) of the        luma coding unit that covers the luma location (xCb+cbWidth/2,        yCb+cbHeight/2).    -   The variables qP_(Cb), qP_(Cr) and qP_(CbCr) are derived as        follows:        qPi_(chroma)=Clip3(−QpBdOffset_(C),63,Qp_(Y))   (8-935)        qPi_(Cb)=ChromaQpTable[0][qPi_(Chroma)]   (8-936)        qPi_(Cr)=ChromaQpTable[1][qPi_(Chroma)]   (8-937)        qPi_(CbCr)=ChromaQpTable[2][qPi_(Chroma)]   (8-938)    -   The chroma quantization parameters for the Cb and Cr components,        Qp′_(Cb) and Qp′_(Cr), and joint Cb-Cr coding Qp′_(CbCr) are        derived as follows:        Qp′_(Cb)=Clip3(−QpBdOffset_(C),63,qP_(Cb)+pps_cb_qp_offset+slice_cb_qp_offset+CuQpOffset_(Cb))+QpBdOffset_(C)  (8-939)        Qp′_(Cr)=Clip3(−QpBdOffset_(C),63,qP_(Cr)+pps_cr_qp_offset+slice_cr_qp_offset+CuQpOffset_(Cr))+QpBdOffset_(C)  (8-940)        Qp′_(CbCr)=Clip3(−QpBdOffset_(C),63,qP_(CbCr)+pps_cbcr_qp_offset+slice_cbcr_qp_offset+CuQpOffset_(CbCr))+QpBdOffset_(C)  (8-941)        8.7.3 Scaling Process for Transform Coefficients        Inputs to this process are:    -   a luma location (xTbY, yTbY) specifying the top-left sample of        the current luma transform block relative to the top-left luma        sample of the current picture,    -   a variable nTbW specifying the transform block width,    -   a variable nTbH specifying the transform block height,    -   a variable cIdx specifying the colour component of the current        block,    -   a variable bitDepth specifying the bit depth of the current        colour component.        Output of this process is the (nTbW)×(nTbH) array d of scaled        transform coefficients with elements d[x][y].        The quantization parameter qP is derived as follows:    -   If cIdx is equal to 0 and transform_skip_flag[xTbY][yTbY] is        equal to 0, the following applies:        qP=Qp′_(Y)  (8-950)    -   Otherwise, if cIdx is equal to 0 (and        transform_skip_flag[xTbY][yTbY] is equal to 1), the following        applies:        qP=Max(QpPrimeTsMin,Qp′_(Y))  (8-951)    -   Otherwise, if TuCResMode[xTbY][yTbY] is equal to 2, the        following applies:        qP=Qp′_(CbCr)  (8-952)    -   Otherwise, if cIdx is equal to 1, the following applies:        qP=Qp′_(Cb)  (8-953)    -   Otherwise (cIdx is equal to 2), the following applies:        qP=Qp′_(Cr)  (8-954)

2.7. Cross-Component Adaptive Loop Filter (CC-ALF)

FIG. 14A illustrates the placement of CC-ALF with respect to the otherloop filters. CC-ALF operates by applying a linear, diamond shapedfilter (FIG. 14B) to the luma channel for each chroma component, whichis expressed as

${{\Delta{I_{i}\left( {x,y} \right)}} = {\sum\limits_{{({x_{0},y_{0}})} \in S_{i}}{{I_{0}\left( {{x_{C} + x_{0}},{y_{C} + y_{0}}} \right)}{c_{i}\left( {x_{0},y_{0}} \right)}}}},$where

-   -   (x, y) is chroma component i location being refined    -   (x_(c), y_(c)) is the luma location based on (x, y)    -   S_(i) is filter support in luma for chroma component i    -   c_(i)(x₀, y₀) represents the filter coefficients        Key features characteristics of the CC-ALF process include:    -   The luma location (x_(c), y_(c)), around which the support        region is centered, is computed based on the spatial scaling        factor between the luma and chroma planes.    -   All filter coefficients are transmitted in the APS and have        8-bit dynamic range.    -   An APS may be referenced in the slice header.    -   CC-ALF coefficients used for each chroma component of a slice        are also stored in a buffer corresponding to a temporal        sublayer. Reuse of these sets of temporal sublayer filter        coefficients is facilitated using slice-level flags.    -   The application of the CC-ALF filters is controlled on a        variable block size and signalled by a context-coded flag        received for each block of samples. The block size along with an        CC-ALF enabling flag is received at the slice-level for each        chroma component.    -   Boundary padding for the horizontal virtual boundaries makes use        of repetition. For the remaining boundaries the same type of        padding is used as for regular ALF.

2.8 Derivation Process for Quantization Parameters

The QP is derived based on neighboring QPs and the decoded delta QP. Thetexts related to QP derivation in JVET-P2001-vE is given as follows.

Inputs to this process are:

-   -   a luma location (xCb, yCb) specifying the top-left luma sample        of the current coding block relative to the top-left luma sample        of the current picture,    -   a variable cbWidth specifying the width of the current coding        block in luma samples,    -   a variable cbHeight specifying the height of the current coding        block in luma samples,    -   a variable treeType specifying whether a single tree        (SINGLE_TREE) or a dual tree is used to partition the coding        tree node and, when a dual tree is used, whether the luma        (DUAL_TREE_LUMA) or chroma components (DUAL_TREE_CHROMA) are        currently processed.        In this process, the luma quantization parameter Qp′Y and the        chroma quantization parameters Qp′Cb, Qp′Cr and Qp′CbCr are        derived.        The luma location (xQg, yQg), specifies the top-left luma sample        of the current quantization group relative to the top left luma        sample of the current picture. The horizontal and vertical        positions xQg and yQg are set equal to CuQgTopLeftX and        CuQgTopLeftY, respectively.        NOTE—: The current quantization group is a rectangular region        inside a coding tree block that shares the same qPY_PRED. Its        width and height are equal to the width and height of the coding        tree node of which the top-left luma sample position is assigned        to the variables CuQgTopLeftX and CuQgTopLeftY.        When treeType is equal to SINGLE_TREE or DUAL_TREE_LUMA, the        predicted luma quantization parameter qPY_PRED is derived by the        following ordered steps:        1. The variable qPY_PREV is derived as follows:    -   If one or more of the following conditions are true, qPY_PREV is        set equal to SliceQpY:    -   The current quantization group is the first quantization group        in a slice.    -   The current quantization group is the first quantization group        in a tile.    -   The current quantization group is the first quantization group        in a CTB row of a tile and entropy_coding_sync_enabled_flag is        equal to 1.    -   Otherwise, qPY_PREV is set equal to the luma quantization        parameter QpY of the last luma coding unit in the previous        quantization group in decoding order.        2. The derivation process for neighbouring block availability as        specified in clause 6.4.4 is invoked with the location (xCurr,        yCurr) set equal to (xCb, yCb), the neighbouring location (xNbY,        yNbY) set equal to (xQg−1, yQg), checkPredModeY set equal to        FALSE, and cIdx set equal to 0 as inputs, and the output is        assigned to availableA. The variable qPY_A is derived as        follows:    -   If one or more of the following conditions are true, qPY_A is        set equal to qPY_PREV:    -   availableA is equal to FALSE.    -   The CTB containing the luma coding block covering the luma        location (xQg−1, yQg) is not equal to the CTB containing the        current luma coding block at (xCb, yCb), i.e. all of the        following conditions are true:    -   (xQg−1)>>CtbLog2SizeY is not equal to (xCb)>>CtbLog2SizeY    -   (yQg)>>CtbLog2SizeY is not equal to (yCb)>>CtbLog2SizeY    -   Otherwise, qPY_A is set equal to the luma quantization parameter        QPY of the coding unit containing the luma coding block covering        (xQg−1, yQg).        3. The derivation process for neighbouring block availability as        specified in clause 6.4.4 is invoked with the location (xCurr,        yCurr) set equal to (xCb, yCb), the neighbouring location (xNbY,        yNbY) set equal to (xQg, yQg−1), checkPredModeY set equal to        FALSE, and cIdx set equal to 0 as inputs, and the output is        assigned to availableB. The variable qPY_B is derived as        follows:    -   If one or more of the following conditions are true, qPY_B is        set equal to qPY_PREV:    -   availableB is equal to FALSE.    -   The CTB containing the luma coding block covering the luma        location (xQg, yQg−1) is not equal to the CTB containing the        current luma coding block at (xCb, yCb), i.e. all of the        following conditions are true:    -   (xQg) CtbLog2SizeY is not equal to (xCb) CtbLog2SizeY    -   (yQg−1) CtbLog2SizeY is not equal to (yCb) CtbLog2SizeY    -   Otherwise, qPY_B is set equal to the luma quantization parameter        Qp_(Y) of the coding unit containing the luma coding block        covering (xQg, yQg−1).        4. The predicted luma quantization parameter qPY_PRED is derived        as follows:    -   If all the following conditions are true, then qPY_PRED is set        equal to the luma quantization parameter QpY of the coding unit        containing the luma coding block covering (xQg, yQg−1):    -   availableB is equal to TRUE.    -   The current quantization group is the first quantization group        in a CTB row within a tile.    -   Otherwise, qPY_PRED is derived as follows:        qPY_PRED=(qPY_A+qPY_B+1)>>1  (1115)        The variable QPY is derived as follows:        QpY=((qPY_PRED+CuQpDeltaVal+64+2*QpBdOffset)%(64+QpBdOffset))−QpBdOffset  (1116)        The luma quantization parameter Qp′Y is derived as follows:        Qp′Y=QpY+QpBdOffset  (1117)        When ChromaArrayType is not equal to 0 and treeType is equal to        SINGLE_TREE or DUAL_TREE_CHROMA, the following applies:    -   When treeType is equal to DUAL_TREE_CHROMA, the variable QpY is        set equal to the luma quantization parameter QpY of the luma        coding unit that covers the luma location (xCb+cbWidth/2,        yCb+cbHeight/2).    -   The variables qPCb, qPCr and qPCbCr are derived as follows:        qPChroma=Clip3(−QpBdOffset,63,QpY)  (1118)        qPCb=ChromaQpTable[0][qPChroma]  (1119)        qPCr=ChromaQpTable[1][qPChroma]  (1120)        qPCbCr=ChromaQpTable[2][qPChroma]  (1121)    -   The chroma quantization parameters for the Cb and Cr components,        Qp′Cb and Qp′Cr, and joint Cb-Cr coding Qp′CbCr are derived as        follows:        Qp′Cb=Clip3(−QpBdOffset,63,qPCb+pps_cb_qp_offset+slice_cb_qp_offset+CuQpOffsetCb)+QpBdOffset  (1122)        Qp′Cr=Clip3(−QpBdOffset,63,qPCr+pps_cr_qp_offset+slice_cr_qp_offset+CuQpOffsetCr)+QpBdOffset  (1123)        Qp′CbCr=Clip3(−QpBdOffset,63,qPCbCr+pps_joint_cbcr_qp_offset+slice_joint_cbcr_qp_offset+CuQpOffsetCbCr)+QpBdOffset  (1124)

2.9 Adaptive Color Transform (ACT)

FIG. 15 illustrates the decoding flowchart with the ACT be applied. Asillustrated in the figure, the color space conversion is carried out inresidual domain. Specifically, one additional decoding module, namelyinverse ACT, is introduced after inverse transform to convert theresiduals from YCgCo domain back to the original domain.In the VVC, unless the maximum transform size is smaller than the widthor height of one coding unit (CU), one CU leaf node is also used as theunit of transform processing. Therefore, in the proposed implementation,the ACT flag is signaled for one CU to select the color space for codingits residuals. Additionally, following the HEVC ACT design, for interand IBC CUs, the ACT is only enabled when there is at least one non-zerocoefficient in the CU. For intra CUs, the ACT is only enabled whenchroma components select the same intra prediction mode of lumacomponent, i.e., DM mode.The core transforms used for the color space conversions are kept thesame as that used for the HEVC. Specifically, the following forward andinverse YCgCo color transform matrices, as described as follows, asapplied.

$\begin{bmatrix}C_{0}^{\prime} \\C_{1}^{\prime} \\C_{2}^{\prime}\end{bmatrix} = {{\begin{bmatrix}2 & 1 & 1 \\2 & {- 1} & {- 1} \\0 & {- 2} & 2\end{bmatrix}\begin{bmatrix}C_{0} \\C_{1} \\C_{2}\end{bmatrix}}/\begin{matrix}4 & {\begin{bmatrix}C_{0} \\C_{1} \\C_{2}\end{bmatrix} = {\begin{bmatrix}1 & 1 & 0 \\1 & {- 1} & {- 1} \\1 & {- 1} & 1\end{bmatrix}\begin{bmatrix}C_{0}^{\prime} \\C_{1}^{\prime} \\C_{2}^{\prime}\end{bmatrix}}}\end{matrix}}$Additionally, to compensate the dynamic range change of residualssignals before and after color transform, the QP adjustments of (−5, −5,−3) are applied to the transform residuals.On the other hand, as shown in FIG. 15 ), the forward and inverse colortransforms need to access the residuals of all three components.Correspondingly, in the proposed implementation, the ACT is disabled inthe following two scenarios where not all residuals of three componentsare available.

-   1. Separate-tree partition: when separate-tree is applied, luma and    chroma samples inside one CTU are partitioned by different    structures. This results in that the CUs in the luma-tree only    contains luma component and the CUs in the chroma-tree only contains    two chroma components.    Intra sub-partition prediction (ISP): the ISP sub-partition is only    applied to luma while chroma signals are coded without splitting. In    the current ISP design, except the last ISP sub-partitions, the    other sub-partitions only contain luma component.

2.10 High-Level Deblocking Control in the VVC Draft 7

The control mechanism is shown in the following FIG. 16 .

3. Drawbacks of Existing Implementations

DMVR and BIO do not involve the original signal during refining themotion vectors, which may result in coding blocks with inaccurate motioninformation. Also, DMVR and BIO sometimes employ the fractional motionvectors after the motion refinements while screen videos usually haveinteger motion vectors, which makes the current motion information moreinaccurate and make the coding performance worse.

-   -   1. The interaction between chroma QP table and chroma deblocking        may have problems, e.g. chroma QP table should be applied to        individual QP but not weighted sum of QPs.    -   2. The logic of luma deblocking filtering process is complicated        for hardware design.    -   3. The logic of boundary strength derivation is too complicated        for both software and hardware design.    -   4. In the BS decision process, JCCR is treated separately from        those blocks coded without JCCT applied. However, JCCR is only a        special way to code the residual. Therefore, such design may        bring additional complexity without no clear benefits.    -   5. In chroma edge decision, Qp_(Q) and Qp_(P) are set equal to        the Qp_(Y) values of the coding units which include the coding        blocks containing the sample q_(0,0) and p_(0,0), respectively.        However, in the quantization/de-quantization process, the QP for        a chroma sample is derived from the QP of luma block covering        the corresponding luma sample of the center position of current        chroma CU. When dual tree is enabled, the different locations of        luma blocks may result in different QPs. Therefore, in the        chroma deblocking process, wrong QPs may be used for filter        decision. Such a misalignment may result in visual artifacts. An        example is shown in FIG. 9A-9B, including FIGS. 9A-9B In FIG.        9A-9B, the left side (FIG. 9A) is the corresponding CTB        partitioning for luma block and the right side (FIG. 9B) in the        chroma CTB partitioning under dual tree. When determining the QP        for chroma block, denoted by CU_(c)1, the center position of        CU_(c)1 is firstly derived. Then the corresponding luma sample        of the center position of CU_(c)1 is identified and luma QP        associated with the luma CU that covers the corresponding luma        sample, i.e., CU_(Y)3 is then utilized to derive the QP for        CU_(c)1. However, when making filter decisions for the depicted        three samples (with solid circles), the QPs of CUs that cover        the corresponding 3 samples are selected. Therefore, for the        1^(st), 2^(nd), and 3^(rd) chroma sample (depicted in FIG. 9B),        the QPs of CU_(Y)2, CU_(Y)3, CU_(Y)4 are utilized, respectively.        That is, chroma samples in the same CU may use different QPs for        filter decision which may result in wrong decisions.    -   6. A different picture level QP offset (i.e.,        pps_joint_cbcr_qp_offset) is applied to JCCR coded blocks which        is different from the picture level offsets for Cb/Cr (e.g.,        pps_cb_qp_offset and pps_cr_qp_offset) applied to non-JCCR coded        blocks. However, in the chroma deblocking filter decision        process, only those offsets for non-JCCR coded blocks are        utilized. The missing of consideration of coded modes may result        in wrong filter decision.    -   7. The TS and non-TS coded blocks employ different QPs in the        de-quantization process, which may be also considered in the        deblocking process.    -   8. Different QPs are used in the scaling process        (quantization/dequantization) for JCCR coded blocks with        different modes. Such a design is not consistent.    -   9. The chroma deblocking for Cb/Cr could be unified for parallel        design.    -   10. The chroma QP in the deblocking is derived based on the QP        used in the chroma dequantization process (e.g. qP), however,        the qP should be clipped or minus 5 for TS and ACT blocks when        it is used in the deblocking process.    -   11. The prediction process for three components may be not same        when both BDPCM and ACT are enabled.

4. Example Techniques and Embodiments

The detailed embodiments described below should be considered asexamples to explain general concepts. These embodiments should not beinterpreted narrowly way. Furthermore, these embodiments can be combinedin any manner.

The proposed methods described below may be applied to the deblockingfilter. Alternatively, they may be applied to other kinds of in-loopfilters, e.g., those rely on quantization parameters.

The methods described below may be also applicable to other decodermotion information derivation technologies in addition to the DMVR andBIO mentioned below.

In the following examples, MVM[i].x and MVM[i].y denote the horizontaland vertical component of the motion vector in reference picture list i(i being 0 or 1) of the block at M (M being P or Q) side. Abs denotesthe operation to get the absolute value of an input, and “&&” and “∥”denotes the logical operation AND and OR. Referring to FIG. 10 , P maydenote the samples at P side and Q may denote the samples at Q side. Theblocks at P side and Q side may denote the block marked by the dashlines.

Regarding Chroma QP in Deblocking

-   1. When chroma QP table is used to derive parameters to control    chroma deblocking (e.g., in the decision process for chroma block    edges), chroma QP offsets may be applied after applying chroma QP    table.    -   a. In one example, the chroma QP offsets may be added to the        value outputted by a chroma QP table.    -   b. Alternatively, the chroma QP offsets may be not considered as        input to a chroma QP table.    -   c. In one example, the chroma QP offsets may be the        picture-level or other video unit-level        (slice/tile/brick/subpicture) chroma quantization parameter        offset (e.g., pps_cb_qp_offset, pps_cr_qp_offset in the        specification).-   2. QP clipping may be not applied to the input of a chroma QP table.-   3. It is proposed that deblocking process for chroma components may    be based on the mapped chroma QP (by the chroma QP table) on each    side.    -   a. In one example, it is proposed that deblocking parameters,        (e.g., β and tC) for chroma may be based on QP derived from luma        QP on each side.    -   b. In one example, the chroma deblocking parameter may depend on        chroma QP table value with QpP as the table index, where QpP, is        the luma QP value on P-side.    -   c. In one example, the chroma deblocking parameter may depend on        chroma QP table value with QpQ as the table index, where QpQ, is        the luma QP value on Q-side.-   4. It is proposed that deblocking process for chroma components may    be based on the QP applied to quantization/dequantization for the    chroma block.    -   a. In one example, QP for deblocking process may be equal to the        QP in dequantization.    -   b. In one example, the QP selection for deblocking process may        depend on the indication of usage of TS and/or ACT blocks.        -   i. In one example, the QP for the deblocking process may be            derived by Max(QpPrimeTsMin,            qP)−(cu_act_enabled_flag[xTbY][yTbY]? N:0), where            QpPrimeTsMin is the minimal QP for TS blocks and            cu_act_enabled_flag is the flag of usage of ACT.            -   1. In one example, qP may be the Qp′_(Cb) or Qp′_(Cr)                given in section 2.8.        -   ii. In one example, the QP for the deblocking process may be            derived by Max(QpPrimeTsMin,            qP−(cu_act_enabled_flag[xTbY][yTbY]? N:0)), where            QpPrimeTsMin is the minimal QP for TS blocks and            cu_act_enabled_flag is the flag of usage of ACT.            -   1. In one example, qP may be the Qp′_(Cb) or Qp′_(Cr)                given in section 2.8.        -   iii. In the above examples, N may be set to same or            different values for each color component.            -   1. In one example, N may be set to 5 for the Cb/B/G/U/                component and/or N may be set to 3 for the Cr/R/B/V                component.    -   c. In one example, the QP of a block used in the deblocking        process may be derived by the process described in section 2.8        with delta QP (e.g. CuQpDeltaVal) equal to 0.        -   i. In one example, the above derivation may be applied only            when the coded block flag (cbf) of a block is equal to 0.    -   d. In one example, the above examples may be applied on luma        and/or chroma blocks.    -   e. In one example, the QP of a first block used in the        deblocking process may be set equal to the QP stored and        utilized for predicting a second block.        -   i. In one example, for a block with all zero coefficients,            the associated QP used in the deblocking process may be set            equal to the QP stored and utilized for predicting a second            block.-   5. It is proposed to consider the    picture/slice/tile/brick/subpicture level quantization parameter    offsets used for different coding methods in the deblocking filter    decision process.    -   a. In one example, selection of        picture/slice/tile/brick/subpicture level quantization parameter        offsets for filter decision (e.g., the chroma edge decision in        the deblocking filter process) may depend on the coded methods        for each side.    -   b. In one example, the filtering process (e.g., the chroma edge        decision process) which requires to use the quantization        parameters for chroma blocks may depend on whether the blocks        use JCCR.        -   i. Alternatively, furthermore, the picture/slice-level QP            offsets (e.g., ppsjoint_cbcr_qp_offset) applied to JCCR            coded blocks may be further taken into consideration in the            deblocking filtering process.        -   ii. In one example, the cQpPicOffset which is used to decide            Tc and R settings may be set to ppsjoint_cbcr_qp_offset            instead of pps_cb_qp_offset or pps_cr_qp_offset under            certain conditions:            -   1. In one example, when either block in P or Q sides                uses JCCR.            -   2. In one example, when both blocks in P or Q sides uses                JCCR.        -   iii. Alternatively, furthermore, the filtering process may            depend on the mode of JCCR (e.g., whether mode is equal to            2).-   6. The chroma filtering process (e.g., the chroma edge decision    process) which requires to access the decoded information of a luma    block may utilize the information associated with the same luma    coding block that is used to derive the chroma QP in the    dequantization/quantization process.    -   a. In one example, the chroma filtering process (e.g., the        chroma edge decision process) which requires to use the        quantization parameters for luma blocks may utilize the luma        coding unit covering the corresponding luma sample of the center        position of current chroma CU.    -   b. An example is depicted in FIGS. 9A-9B wherein the decoded        information of CU_(Y)3 may be used for filtering decision of the        three chroma samples (1^(st), 2^(nd) and 3^(rd)) in FIG. 9B.-   7. The chroma filtering process (e.g., the chroma edge decision    process) may depend on the quantization parameter applied to the    scaling process of the chroma block (e.g.,    quantization/dequantization).    -   a. In one example, the QP used to derive β and Tc may depend on        the QP applied to the scaling process of the chroma block.    -   b. Alternatively, furthermore, the QP used to the scaling        process of the chroma block may have taken the chroma CU level        QP offset into consideration.-   8. Whether to invoke above bullets may depend on the sample to be    filtered is in the block at P or Q side.    -   a. For example, whether to use the information of the luma        coding block covering the corresponding luma sample of current        chroma sample or use the information of the luma coding block        covering the corresponding luma sample of center position of        chroma coding block covering current chroma sample may depend on        the block position.        -   i. In one example, if the current chroma sample is in the            block at the Q side, QP information of the luma coding block            covering the corresponding luma sample of center position of            chroma coding block covering current chroma sample may be            used.        -   ii. In one example, if the current chroma sample is in the            block at the P side, QP information of the luma coding block            covering the corresponding luma sample of the chroma sample            may be used.-   9. Chroma QP used in deblocking may depend on information of the    corresponding transform block.    -   a. In one example, chroma QP for deblocking at P-side may depend        on the transform block's mode at P-side.        -   i. In one example, chroma QP for deblocking at P-side may            depend on if the transform block at P-side is coded with            JCCR applied.        -   ii. In one example, chroma QP for deblocking at P-side may            depend on if the transform block at P-side is coded with            joint_cb_cr mode and the mode of JCCR is equal to 2.    -   b. In one example, chroma QP for deblocking at Q-side may depend        on the transform block's mode at Q-side.        -   i. In one example, chroma QP for deblocking at Q-side may            depend on if the transform block at Q-side is coded with            JCCR applied.        -   ii. In one example, chroma QP for deblocking at Q-side may            depend on if the transform block at Q-side is coded with            JCCR applied and the mode of JCCR is equal to 2.-   10. Signaling of chroma QPs may be in coding unit.    -   a. In one example, when coding unit size is larger than the        maximum transform block size, i.e., maxTB, chroma QP may be        signaled in CU level. Alternatively, it may be signaled in TU        level.    -   b. In one example, when coding unit size is larger than the size        of VPDU, chroma QP may be signaled in CU level. Alternatively,        it may be signaled in TU level.-   11. Whether a block is of joint_cb_cr mode may be indicated at    coding unit level.    -   a. In one example, whether a transform block is of joint_cb_cr        mode may inherit the information of the coding unit containing        the transform block.-   12. Chroma QP used in deblocking may depend on chroma QP used in    scaling process minus QP offset due to bit depth.    -   a. In one example, Chroma QP used in deblocking at P-side is set        to the JCCR chroma QP used in scaling process, i.e. Qp′_(CbCr),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the first        sample at P-side, i.e. p_(0,0).    -   b. In one example, Chroma QP used in deblocking at P-side is set        to the Cb chroma QP used in scaling process, i.e. Qp′_(Cb),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the first        sample at P-side, i.e. p_(0,0).    -   c. In one example, Chroma QP used in deblocking at P-side is set        to the Cr chroma QP used in scaling process, i.e. Qp′_(Cr),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the first        sample at P-side, i.e. p_(0,0).    -   d. In one example, Chroma QP used in deblocking at Q-side is set        to the JCCR chroma QP used in scaling process, i.e. Qp′_(CbCr),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the last        sample at Q-side, i.e. q_(0,0).    -   e. In one example, Chroma QP used in deblocking at Q-side is set        to the Cb chroma QP used in scaling process, i.e. Qp′_(Cb),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the last        sample at Q-side, i.e. q_(0,0).    -   f. In one example, Chroma QP used in deblocking at Q-side is set        to the Cr chroma QP used in scaling process, i.e. Qp′_(Cr),        minus QpBdOffsetC when TuCResMode[xTb][yTb] is equal to 2 where        (xTb, yTb) denotes the transform blocking containing the last        sample at Q-side, i.e. q_(0,0).-   13. Different color components may have different deblocking    strength control.    -   a. In one example, each component may have its        pps_beta_offset_div2, pps_tc_offset_div2 and/or        pic_beta_offset_div2, pic_tc_offset_div2 and/or        slice_beta_offset_div2, slice_tc_offset_div2.    -   b. In one example, for joint_cb_cr mode, a different set of        beta_offset_div2, tc_offset_div2 may be applied in PPS and/or        picture header and/or slice header.-   14. Instead of using overriding mechanism, the deblocking control    offset may be accumulated taking account of offsets at different    levels.    -   a. In one example, pps_beta_offset_div2 and/or        pic_beta_offset_div2 and/or slice_beta_offset_div2 may be        accumulated to get the deblocking offset at slice level.    -   b. In one example, pps_tc_offset_div2 and/or pic_tc_offset_div2        and/or slice_tc_offset_div2 may be accumulated to get the        deblocking offset at slice level.        Regarding OP Settings-   15. It is proposed to signal the indication of enabling block-level    chroma QP offset (e.g. slice_cu_chroma_qp_offset_enabled_flag) at    the slice/tile/brick/subpicture level.    -   a. Alternatively, the signaling of such an indication may be        conditionally signaled.        -   i. In one example, it may be signaled under the condition of            JCCR enabling flag.        -   ii. In one example, it may be signaled under the condition            of block-level chroma QP offset enabling flag in picture            level.        -   iii. Alternatively, such an indication may be derived            instead.    -   b. In one example, the slice_cu_chroma_qp_offset_enabled_flag        may be signaled only when the PPS flag of chroma QP offset (e.g.        slice_cu_chroma_qp_offset_enabled_flag) is true.    -   c. In one example, the slice_cu_chroma_qp_offset_enabled_flag        may be inferred to false only when the PPS flag of chroma QP        offset (e.g. slice_cu_chroma_qp_offset_enabled_flag) is false.    -   d. In one example, whether to use the chroma QP offset on a        block may be based on the flags of chroma QP offset at PPS level        and/or slice level.-   16. Same QP derivation method is used in the scaling process    (quantization/dequantization) for JCCR coded blocks with different    modes.    -   a. In one example, for JCCR with mode 1 and 3, the QP is        dependent on the QP offset signaled in the picture/slice level        (e.g., pps_cbcr_qp_offset, slice_cbcr_qp_offset).        Filtering Procedures-   17. Deblocking for all color components excepts for the first color    component may follow the deblocking process for the first color    component.    -   a. In one example, when the color format is 4:4:4, deblocking        process for the second and third components may follow the        deblocking process for the first component.    -   b. In one example, when the color format is 4:4:4 in RGB color        space, deblocking process for the second and third components        may follow the deblocking process for the first component.    -   c. In one example, when the color format is 4:2:2, vertical        deblocking process for the second and third components may        follow the vertical deblocking process for the first component.    -   d. In above examples, the deblocking process may refer to        deblocking decision process and/or deblocking filtering process.-   18. How to calculate gradient used in the deblocking filter process    may depend on the coded mode information and/or quantization    parameters.    -   a. In one example, the gradient computation may only consider        the gradient of a side wherein the samples at that side are not        lossless coded.    -   b. In one example, if both sides are lossless coded or nearly        lossless coded (e.g., quantization parameters equal to 4),        gradient may be directly set to 0.        -   i. Alternatively, if both sides are lossless coded or nearly            lossless coded (e.g., quantization parameters equal to 4),            Boundary Strength (e.g., BS) may be set to 0.    -   c. In one example, if the samples at P side are lossless coded        and the samples at Q side are lossy coded, the gradients used in        deblocking on/off decision and/or strong filters on/off decision        may only include gradients of the samples at Q side, vice versa.        -   i. Alternatively, furthermore, the gradient of one side may            be scaled by N.            -   1. N is an integer number (e.g. 2) and may depend on                -   a. Video contents (e.g. screen contents or natural                    contents)                -   b. A message signaled in the                    DPS/SPS/VPS/PPS/APS/picture header/slice header/tile                    group header/Largest coding unit (LCU)/Coding unit                    (CU)/LCU row/group of LCUs/TU/PU block/Video coding                    unit                -   c. Position of CU/PU/TU/block/Video coding unit                -   d. Coded modes of blocks containing the samples                    along the edges                -   e. Transform matrices applied to the blocks                    containing the samples along the edges                -   f. Block dimension/Block shape of current block                    and/or its neighboring blocks                -   g. Indication of the color format (such as 4:2:0,                    4:4:4, RGB or YUV)                -   h. Coding tree structure (such as dual tree or                    single tree)                -   i. Slice/tile group type and/or picture type                -   j. Color component (e.g. may be only applied on Cb                    or Cr)                -   k. Temporal layer ID                -   l. Profiles/Levels/Tiers of a standard                -   m. Alternatively, N may be signalled to the decoder                    Regarding Boundary Strength Derivation-   19. It is proposed to treat JCCR coded blocks as those non-JCCR    coded blocks in the boundary strength decision process.    -   a. In one example, the determination of boundary strength (BS)        may be independent from the checking of usage of JCCR for two        blocks at P and Q sides.    -   a. In one example, the boundary strength (BS) for a block may be        determined regardless if the block is coded with JCCR or not.-   20. It is proposed to derive the boundary strength (BS) without    comparing the reference pictures and/or number of MVs associated    with the block at P side with the reference pictures of the block at    Q side.    -   b. In one example, deblocking filter may be disabled even when        two blocks are with different reference pictures.    -   c. In one example, deblocking filter may be disabled even when        two blocks are with different number of MVs (e.g., one is        uni-predicted and the other is bi-predicted).    -   d. In one example, the value of BS may be set to 1 when motion        vector differences for one or all reference picture lists        between the blocks at P side and Q side is larger than or equal        to a threshold Th.        -   i. Alternatively, furthermore, the value of BS may be set to            0 when motion vector differences for one or all reference            picture lists between the blocks at P side and Q side is            smaller than or equal to a threshold Th.    -   e. In one example, the difference of the motion vectors of two        blocks being larger than a threshold Th may be defined as        (Abs(MVP[0].x−MVQ[0].x)>Th∥Abs(MVP[0].y−MVQ[0].y)>Th∥Abs(MVP[1].x−MVQ[1].x)>Th)∥Abs(MVP[1].y−MVQ[1].y)>Th)        -   i. Alternatively, the difference of the motion vectors of            two blocks being larger than a threshold Th may be defined            as (Abs(MVP[0].x−MVQ[0].x)>Th && Abs(MVP[0].y−MVQ[0].y)>Th            && Abs(MVP[1].x−MVQ[1].x)>Th) && Abs(MVP[1].y−MVQ[1].y)>Th)        -   ii. Alternatively, in one example, the difference of the            motion vectors of two blocks being larger than a threshold            Th may be defined as            (Abs(MVP[0].x−MVQ[0].x)>Th∥Abs(MVP[0].y−MVQ[0].y)>Th) &&            (Abs(MVP[1].x−MVQ[1].x)>Th∥Abs(MVP[1].y−MVQ[1].y)>Th)        -   iii. Alternatively, in one example, the difference of the            motion vectors of two blocks being larger than a threshold            Th may be defined as (Abs(MVP[0].x−MVQ[0].x)>Th &&            Abs(MVP[0].y−MVQ[0].y)>Th)∥(Abs(MVP[1].x−MVQ[1].x)>Th) &&            Abs(MVP[1].y−MVQ[1].y)>Th)    -   f. In one example, a block which does not have a motion vector        in a given list may be treated as having a zero-motion vector in        that list.    -   g. In the above examples, Th is an integer number (e.g. 4, 8 or        16).    -   h. In the above examples, Th may depend on        -   i. Video contents (e.g. screen contents or natural contents)        -   ii. A message signaled in the DPS/SPS/VPS/PPS/APS/picture            header/slice header/tile group header/Largest coding unit            (LCU)/Coding unit (CU)/LCU row/group of LCUs/TU/PU            block/Video coding unit        -   iii. Position of CU/PU/TU/block/Video coding unit        -   iv. Coded modes of blocks containing the samples along the            edges        -   v. Transform matrices applied to the blocks containing the            samples along the edges        -   vi. Block dimension/Block shape of current block and/or its            neighboring blocks        -   vii. Indication of the color format (such as 4:2:0, 4:4:4,            RGB or YUV)        -   viii. Coding tree structure (such as dual tree or single            tree)        -   ix. Slice/tile group type and/or picture type        -   x. Color component (e.g. may be only applied on Cb or Cr)        -   xi. Temporal layer ID        -   xii. Profiles/Levels/Tiers of a standard        -   xiii. Alternatively, Th may be signalled to the decoder.    -   i. The above examples may be applied under certain conditions.        -   i. In one example, the condition is the blkP and blkQ are            not coded with intra modes.        -   ii. In one example, the condition is the blkP and blkQ have            zero coefficients on luma component.        -   iii. In one example, the condition is the blkP and blkQ are            not coded with the CIIP mode.        -   iv. In one example, the condition is the blkP and blkQ are            coded with a same prediction mode (e.g. IBC or Inter).            Regarding Luma Deblocking Filtering Process-   21. The deblocking may use different QPs for TS coded blocks and    non-TS coded blocks.    -   a. In one example, the QP for TS may be used on TS coded blocks        while the QP for non-TS may be used on non-TS coded blocks.-   22. The luma filtering process (e.g., the luma edge decision    process) may depend on the quantization parameter applied to the    scaling process of the luma block.    -   a. In one example, the QP used to derive beta and Tc may depend        on the clipping range of transform skip, e.g. as indicated by        QpPrimeTsMin.-   23. It is proposed to use an identical gradient computation for    large block boundaries and smaller block boundaries.    -   a. In one example, the deblocking filter on/off decision        described in section 2.1.4 may be also applied for large block        boundary.        -   i. In one example, the threshold beta in the decision may be            modified for large block boundary.            -   1. In one example, beta may depend on quantization                parameter.            -   2. In one example, beta used for deblocking filter                on/off decision for large block boundaries may be                smaller than that for smaller block boundaries.                -   a. Alternatively, in one example, beta used for                    deblocking filter on/off decision for large block                    boundaries may be larger than that for smaller block                    boundaries.                -   b. Alternatively, in one example, beta used for                    deblocking filter on/off decision for large block                    boundaries may be equal to that for smaller block                    boundaries.            -   3. In one example, beta is an integer number and may be                based on                -   a. Video contents (e.g. screen contents or natural                    contents)                -   b. A message signaled in the                    DPS/SPS/VPS/PPS/APS/picture header/slice header/tile                    group header/Largest coding unit (LCU)/Coding unit                    (CU)/LCU row/group of LCUs/TU/PU block/Video coding                    unit                -   c. Position of CU/PU/TU/block/Video coding unit                -   d. Coded modes of blocks containing the samples                    along the edges                -   e. Transform matrices applied to the blocks                    containing the samples along the edges                -   f. Block dimension of current block and/or its                    neighboring blocks                -   g. Block shape of current block and/or its                    neighboring blocks                -   h. Indication of the color format (such as 4:2:0,                    4:4:4, RGB or YUV)                -   i. Coding tree structure (such as dual tree or                    single tree)                -   j. Slice/tile group type and/or picture type                -   k. Color component (e.g. may be only applied on Cb                    or Cr)                -   l. Temporal layer ID                -   m. Profiles/Levels/Tiers of a standard                -   n. Alternatively, beta may be signalled to the                    decoder.                    Regarding Scaling Matrix (Dequantization Matrix)-   24. The values for specific positions of quantization matrices may    be set to constant.    -   a. In one example, the position may be the position of (x, y)        wherein x and y are two integer variables (e.g., x=y=0), and        (x, y) is the coordinate relative to a TU/TB/PU/PB/CU/CB.        -   i. In one example, the position may be the position of DC.    -   b. In one example, the constant value may be 16.    -   c. In one example, for those positions, signaling of the matrix        values may not be utilized.-   25. A constrain may be set that the average/weighted average of some    positions of quantization matrices may be a constant.    -   a. In one example, deblocking process may depend on the constant        value.    -   b. In one example, the constant value may be indicated in        DPS/VPS/SPS/PPS/Slice/Picture/Tile/Brick headers.-   26. One or multiple indications may be signaled in the picture    header to inform the scaling matrix to be selected in the picture    associated with the picture header.    Regarding Cross Component Adaptive Loop Filter (CCALF)-   27. CCALF may be applied before some loop filtering process at the    decoder    -   a. In one example, CCALF may be applied before deblocking        process at the decoder.    -   b. In one example, CCALF may be applied before SAO at the        decoder.    -   c. In one example, CCALF may be applied before ALF at the        decoder.    -   d. Alternatively, the order of different filters (e.g., CCALF,        ALF, SAO, deblocking filter) may be NOT fixed.        -   i. In one example, the invoke of CCLAF may be before one            filtering process for one video unit or after another one            for another video unit.        -   ii. In one example, the video unit may be a            CTU/CTB/slice/tile/brick/picture/sequence.    -   e. Alternatively, indications of the order of different filters        (e.g., CCALF, ALF, SAO, deblocking filter) may be signaled or        derived on-the-fly.        -   i. Alternatively, indication of the invoking of CCALF may be            signaled or derived on-the-fly.    -   f. The explicit (e.g. signaling from the encoder to the decoder)        or implicit (e.g. derived at both encoder and decoder)        indications of how to control CCALF may be decoupled for        different color components (such as Cb and Cr).    -   g. Whether and/or how to apply CCALF may depend on color formats        (such as RGB and YCbCr) and/or color sampling format (such as        4:2:0, 4:2:2 and 4:4:4), and/or color down-sampling positions or        phases)        Regarding Chroma QP Offset Lists-   28. Signaling and/or selection of chroma QP offset lists may be    dependent on the coded prediction modes/picture types/slice or tile    or brick types.    -   a. Chroma QP offset lists, e.g. cb_qp_offset_list[i],        cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i], may be        different for different coding modes.    -   b. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in intra        mode.    -   c. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in inter        mode.    -   d. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in        palette mode.    -   e. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in IBC        mode.    -   f. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in        transform skip mode.    -   g. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in BDPCM        mode.    -   h. In one example, whether and how to apply chroma QP offset        lists may depend on whether the current block is coded in        transform_quant_skip or lossless mode.        Regarding Chroma Deblocking at CTU Boundary-   29. How to select the QPs (e.g., using corresponding luma or chroma    dequantized QP) utilized in the deblocking filter process may be    dependent on the position of samples relative to the CTU/CTB/VPDU    boundaries.-   30. How to select the QPs (e.g., using corresponding luma or chroma    dequantized QP) utilized in the deblocking filter process may depend    on color formats (such as RGB and YCbCr) and/or color sampling    format (such as 4:2:0, 4:2:2 and 4:4:4), and/or color down-sampling    positions or phases).-   31. For edges at CTU boundary, the deblocking may be based on luma    QP of the corresponding blocks.    -   a. In one example, for horizontal edges at CTU boundary, the        deblocking may be based on luma QP of the corresponding blocks.        -   i. In one example, the deblocking may be based on luma QP of            the corresponding blocks at P-side.        -   ii. In one example, the deblocking may be based on luma QP            of the corresponding blocks at Q-side.    -   b. In one example, for vertical edges at CTU boundary, the        deblocking may be based on luma QP of the corresponding blocks.        -   i. In one example, the deblocking may be based on luma QP of            the corresponding blocks at P-side.        -   ii. In one example, the deblocking may be based on luma QP            of the corresponding blocks at Q-side.    -   c. In one example, for edges at CTU boundary, the deblocking may        be based on luma QP at P-side and chroma QP at Q-side.    -   d. In one example, for edges at CTU boundary, the deblocking may        be based on luma QP at Q-side and chroma QP at P-side.    -   e. In this bullet, “CTU boundary” may refer to a specific CTU        boundary such as the upper CTU boundary or the lower CTU        boundary.-   32. For horizontal edges at CTU boundary, the deblocking may be    based on a function of chroma QPs at P-side.    -   a. In one example, the deblocking may be based on an averaging        function of chroma QPs at P-side.        -   i. In one example, the function may be based on the average            of the chroma QPs for each 8 luma samples.        -   ii. In one example, the function may be based on the average            of the chroma QPs for each 16 luma samples.        -   iii. In one example, the function may be based on the            average of the chroma QPs for each 32 luma samples.        -   iv. In one example, the function may be based on the average            of the chroma QPs for each 64 luma samples.        -   v. In one example, the function may be based on the average            of the chroma QPs for each CTU.    -   b. In one example, the deblocking may be based on a maximum        function of chroma QPs at P-side.        -   i. In one example, the function may be based on the maximum            of the chroma QPs for each 8 luma samples.        -   ii. In one example, the function may be based on the maximum            of the chroma QPs for each 16 luma samples.        -   iii. In one example, the function may be based on the            maximum of the chroma QPs for each 32 luma samples.        -   iv. In one example, the function may be based on the maximum            of the chroma QPs for each 64 luma samples.        -   v. In one example, the function may be based on the maximum            of the chroma QPs for each CTU.    -   c. In one example, the deblocking may be based on a minimum        function of chroma QPs at P-side.        -   i. In one example, the function may be based on the minimum            of the chroma QPs for each 8 luma samples.        -   ii. In one example, the function may be based on the minimum            of the chroma QPs for each 16 luma samples.        -   iii. In one example, the function may be based on the            minimum of the chroma QPs for each 32 luma samples.        -   iv. In one example, the function may be based on the minimum            of the chroma QPs for each 64 luma samples.        -   v. In one example, the function may be based on the minimum            of the chroma QPs for each CTU.    -   d. In one example, the deblocking may be based on a subsampling        function of chroma QPs at P-side.        -   i. In one example, the function may be based on the chroma            QPs of the k-th chroma sample for each 8 luma samples.            -   1. In one example, the k-th sample may be the first                sample.            -   2. In one example, the k-th sample may be the last                sample.            -   3. In one example, the k-th sample may be the third                sample.            -   4. In one example, the k-th sample may be the fourth                sample.        -   ii. In one example, the function may be based on the chroma            QPs of the k-th chroma sample for each 16 luma samples.            -   1. In one example, the k-th sample may be the first                sample.            -   2. In one example, the k-th sample may be the last                sample.            -   3. In one example, the k-th sample may be the 7-th                sample.            -   4. In one example, the k-th sample may be the 8-th                sample.        -   iii. In one example, the function may be based on the chroma            QPs of the k-th chroma sample for each 32 luma samples.            -   1. In one example, the k-th sample may be the first                sample.            -   2. In one example, the k-th sample may be the last                sample.            -   3. In one example, the k-th sample may be the 15-th                sample.            -   4. In one example, the k-th sample may be the 16-th                sample.        -   iv. In one example, the function may be based on the chroma            QPs of the k-th chroma sample for each 64 luma samples.            -   1. In one example, the k-th sample may be the first                sample.            -   2. In one example, the k-th sample may be the last                sample.            -   3. In one example, the k-th sample may be the 31-th                sample.            -   4. In one example, the k-th sample may be the 32-th                sample.        -   v. In one example, the function may be based on the chroma            QPs of the k-th chroma sample for each CTU.    -   e. Alternatively, the above items may be applied to chroma QPs        at Q-side for deblocking process.-   33. It may be constrained that quantization group for chroma    component must be larger than a certain size.    -   a. In one example, it may be constrained that the width of        quantization group for chroma component must be larger than a        certain value, K.        -   i. In one example, K is equal to 4.-   34. It may be constrained that quantization group for luma component    must be larger than a certain size.    -   a. In one example, it may be constrained that the width of        quantization group for luma component must be larger than a        certain value, K.        -   i. In one example, K is equal to 8.-   35. It may be constrained that QP for chroma component may be the    same for a chroma row segment with length 4*m starting from (4*m*x,    2y) relative to top-left of the picture, where x and y are    non-negative integers; and m is a positive integer.    -   a. In one example, m may be equal to 1.    -   b. In one example, the width of a quantization group for chroma        component must be no smaller than 4*m.-   36. It may be constrained that QP for chroma component may be the    same for a chroma column segment with length 4*n starting from (2*x,    4*n*y) relative to top-left of the picture, where x and y are    non-negative integers; and m is a positive integer.    -   a. In one example, n may be equal to 1.    -   b. In one example, the height of a quantization group for chroma        component must be no smaller than 4*n.        Regarding Chroma Deblocking Filtering Process-   37. A first syntax element controlling the usage of coding tool X    may be signalled in a first video unit (such as picture header),    depending on a second syntax element signalled in a second video    unit (such as SPS or PPS, or VPS).    -   a. In one example, the first syntax element is signalled only if        the second syntax element indicates that the coding tool X is        enabled.    -   b. In one example, X is Bi-Direction Optical Flow (BDOF).    -   c. In one example, X is Prediction Refinement Optical Flow        (PROF).    -   d. In one example, X is Decoder-side Motion Vector Refinement        (DMVR).    -   e. In one example, the signalling of the usage of a coding tool        X may be under the condition check of slice types (e.g., P or B        slices; non-I slices).        Regarding Chroma Deblocking Filtering Process-   38. Deblocking filter decision processes for two chroma blocks may    be unified to be only invoked once and the decision is applied to    two chroma blocks.    -   b. In one example, the decision for whether to perform        deblocking filter may be same for Cb and Cr components.    -   c. In one example, if the deblocking filter is determined to be        applied, the decision for whether to perform stronger deblocking        filter may be same for Cb and Cr components.    -   d. In one example, the deblocking condition and strong filter        on/off condition, as described in section 2.2.7, may be only        checked once. However, it may be modified to check the        information of both chroma components.        -   i. In one example, the average of gradients of Cb and Cr            components may be used in the above decisions for both Cb            and Cr components.        -   ii. In one example, the chroma stronger filters may be            performed only when the strong filter condition is satisfied            for both Cb and Cr components.            -   1. Alternatively, in one example, the chroma weak                filters may be performed only when the strong filter                condition is not satisfied at least one chroma component                On ACT-   39. Whether deblocking QP is equal to dequantization QP may depend    on whether ACT is applied.    -   a. In one example, when ACT is applied to a block, deblocking QP        values may depend on QP values before ACT QP adjustment.    -   b. In one example, when ACT is not applied to a block,        deblocking QP values may always equal to dequantization QP        values.    -   c. In one example, when both ACT and TS are not applied to a        block, deblocking QP values may always equal to dequantization        QP values.-   40. ACT and BDPCM may be applied exclusively at block level.    -   a. In one example, when ACT is applied on a block, luma BDPCM        shall not be applied on that block.    -   b. In one example, when ACT is applied on a block, chroma BDPCM        shall not be applied on that block.    -   c. In one example, when ACT is applied on a block, both luma and        chroma BDPCM shall not be applied on that block.    -   d. In one example, when luma and/or chroma BDPCM is applied on a        block, ACT shall not be applied on that block.-   41. Whether to enable BDPCM mode may be inferred based on the usage    of ACT (e.g. cu_act_enabled_flag).    -   a. In one example, the inferred value of chroma BDPCM mode may        be defined as (cu_act_enabled_flag && intra_bdpcm_luma_flag &&        sps_bdpcm_chroma_enabled_flag? true: false).    -   b. In one example, if sps_bdpcm_chroma_enabled_flag is false,        the intra_bdpcm_luma_flag may be inferred to false when it is        not signalled and cu_act_enabled_flag is true.    -   c. In one example, the cu_act_enabled_flag may be inferred to        false when intra_bdpcm_luma_flag is true and        sps_bdpcm_chroma_enabled_flag is false.    -   d. In one example, the intra_bdpcm_luma_flag may be inferred to        false when cu_act_enabled_flag is true and        sps_bdpcm_chroma_enabled_flag is false.        General Claims-   42. The above proposed methods may be applied under certain    conditions.    -   a. In one example, the condition is the colour format is 4:2:0        and/or 4:2:2.        -   i. Alternatively, furthermore, for 4:4:4 colour format, how            to apply deblocking filter to the two colour chroma            components may follow the current design.    -   b. In one example, indication of usage of the above methods may        be signalled in sequence/picture/slice/tile/brick/a video        region-level, such as SPS/PPS/picture header/slice header.    -   c. In one example, the usage of above methods may depend on        -   ii. Video contents (e.g. screen contents or natural            contents)        -   iii. A message signaled in the DPS/SPS/VPS/PPS/APS/picture            header/slice header/tile group header/Largest coding unit            (LCU)/Coding unit (CU)/LCU row/group of LCUs/TU/PU            block/Video coding unit        -   iv. Position of CU/PU/TU/block/Video coding unit            -   a. In one example, for filtering samples along the                CTU/CTB boundaries (e.g., the first K (e.g., K=4/8) to                the top/left/right/bottom boundaries), the existing                design may be applied. While for other samples, the                proposed method (e.g., bullets 3/4) may be applied                instead.        -   v. Coded modes of blocks containing the samples along the            edges        -   vi. Transform matrices applied to the blocks containing the            samples along the edges        -   vii. Block dimension of current block and/or its neighboring            blocks        -   viii. Block shape of current block and/or its neighboring            blocks        -   ix. Indication of the color format (such as 4:2:0, 4:4:4,            RGB or YUV)        -   x. Coding tree structure (such as dual tree or single tree)        -   xi. Slice/tile group type and/or picture type        -   xii. Color component (e.g. may be only applied on Cb or Cr)        -   xiii. Temporal layer ID        -   xiv. Profiles/Levels/Tiers of a standard        -   xv. Alternatively, m and/or n may be signalled to the            decoder.

5. Additional Embodiments

The embodiments are based on JVET-02001-vE. The newly added texts areshown in underlined bold italicized font. The deleted texts are markedby underlined bold font.

5.1. Embodiment #1 on Chroma QP in Deblocking

8.8.3.6 Edge Filtering Process for One Direction

. . .

-   -   Otherwise (cIdx is not equal to 0), the filtering process for        edges in the chroma coding block of current coding unit        specified by cIdx consists of the following ordered steps:

1. The variable cQpPicOffset is derived as follows:cQpPicOffset=cIdx==1?pps_cb_qp_offset:pps_cr_qp_offset  (8-1065)8.8.3.6.3 Decision Process for Chroma Block EdgesThe variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y) values ofthe coding units which include the coding blocks containing the sampleq_(0,0) and p_(0,0), respectively.The variable Qp_(C) is derived as follows:qPi=Clip3(0,63,((Qp_(Q)+Qp_(P)+1)>>1)+cQpPicOffset)  (8-1132)Qp_(C)=ChromaQpTable[cIdx−1][qPi]  (8-1133)qPi=(Qp_(Q)+Qp_(P)+1)>>1  (8-1132)Qp_(C)=ChromaQpTable[cIdx−1][qPi]+cQpPicOffset  (8-1133)NOTE—The variable cQpPicOffset provides an adjustment for the value ofpps_cb_qp_offset or pps_cr_qp_offset, according to whether the filteredchroma component is the Cb or Cr component. However, to avoid the needto vary the amount of the adjustment within the picture, the filteringprocess does not include an adjustment for the value ofslice_cb_qp_offset or slice_cr_qp_offset nor (whencu_chroma_qp_offset_enabled_flag is equal to 1) for the value ofCuQpOffset_(Cb), CuQpOffset_(Cr), or CuQpOffset_(CbCr).

The value of the variable β′ is determined as specified in Table 8-18based on the quantization parameter Q derived as follows:Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (8-1134)where slice_beta_offset_div2 is the value of the syntax elementslice_beta_offset_div2 for the slice that contains sample q_(0,0).The variable β is derived as follows:β=β′*(1<<(BitDepth_(C)−8))  (8-1135)The value of the variable t_(C)′ is determined as specified in Table8-18 based on the chroma quantization parameter Q derived as follows:Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (8-1136)where slice_tc_offset_div2 is the value of the syntax elementslice_tc_offset_div2 for the slice that contains sample q_(0,0).

The variable t_(C) is derived as follows:t _(C)(BitDepth_(C)<10)?(t _(C)′+2)>>(10−BitDepth_(C)):t_(C)′*(1<<(BitDepth_(C)−8))   (8-1137)

5.2. Embodiment #2 on Boundary Strength Derivation

8.8.3.5 Derivation Process of Boundary Filtering Strength

Inputs to this process are:

-   -   a picture sample array recPicture,    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,    -   a variable nCbW specifying the width of the current coding        block,    -   a variable nCbH specifying the height of the current coding        block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable cIdx specifying the colour component of the current        coding block,    -   a two-dimensional (nCbW)×(nCbH) array edgeFlags.        Output of this process is a two-dimensional (nCbW)×(nCbH) array        bS specifying the boundary filtering strength.        . . .        For xD_(i) with i=0 . . . xN and yD_(j) with j=0 . . . yN, the        following applies:    -   If edgeFlags[xD_(i)][yD_(j)] is equal to 0, the variable        bS[xD_(i)][yD_(j)] is set equal to 0.    -   Otherwise, the following applies:        -   . . .        -   The variable bS[xD_(i)][yD_(j)] is derived as follows:            -   If cIdx is equal to 0 and both samples p₀ and q₀ are in                a coding block with intra_bdpcm_flag equal to 1,                bS[xD_(i)][yD_(j)] is set equal to 0.            -   Otherwise, if the sample p₀ or q₀ is in the coding block                of a coding unit coded with intra prediction mode,                bS[xD_(i)][yD_(j)] is set equal to 2.            -   Otherwise, if the block edge is also a transform block                edge and the sample p₀ or q₀ is in a coding block with                ciip_flag equal to 1, bS[xD_(i)][yD_(j)] is set equal to                2.            -   Otherwise, if the block edge is also a transform block                edge and the sample p₀ or q₀ is in a transform block                which contains one or more non-zero transform                coefficient levels, bS[xD_(i)][yD_(j)] is set equal to                1.            -   Otherwise, if the block edge is also a transform block                edge, cIdx is greater than 0, and the sample p₀ or q₀ is                in a transform unit with tu_joint_cbcr_residual_flag                equal to 1, bS[xD_(i)][yD_(j)] is set equal to 1.            -   Otherwise, if the prediction mode of the coding subblock                containing the sample p₀ is different from the                prediction mode of the coding subblock containing the                sample q₀ (i.e. one of the coding subblock is coded in                IBC prediction mode and the other is coded in inter                prediction mode), bS[xD_(i)][yD_(j)] is set equal to 1.            -   Otherwise, if cIdx is equal to 0 and one or more of the                following conditions are true, bS[xD_(i)][yD_(j)] is set                equal to 1:                -   

                -   The coding subblock containing the sample p₀ and the                    coding subblock containing the sample q₀ are both                    coded in IBC prediction mode, and the absolute                    difference between the horizontal or vertical                    component of the block vectors used in the                    prediction of the two coding subblocks is greater                    than or equal to 8 in units of 1/16 luma samples.

                -   For the prediction of the coding subblock containing                    the sample p₀ different reference pictures or a                    different number of motion vectors are used than for                    the prediction of the coding subblock containing the                    sample q₀.

                -    NOTE 1—The determination of whether the reference                    pictures used for the two coding subblocks are the                    same or different is based only on which pictures                    are referenced, without regard to whether a                    prediction is formed using an index into reference                    picture list 0 or an index into reference picture                    list 1, and also without regard to whether the index                    position within a reference picture list is                    different.

                -    NOTE 2—The number of motion vectors that are used                    for the prediction of a coding subblock with                    top-left sample covering (xSb, ySb), is equal to                    PredFlagL0[xSb][ySb]+PredFlagL1[xSb][ySb].

                -   One motion vector is used to predict the coding                    subblock containing the sample p₀ and one motion                    vector is used to predict the coding subblock                    containing the sample q₀, and the absolute                    difference between the horizontal or vertical                    component of the motion vectors used is greater than                    or equal to 8 in units of 1/16 luma samples.

                -   Two motion vectors and two different reference                    pictures are used to predict the coding subblock                    containing the sample p₀, two motion vectors for the                    same two reference pictures are used to predict the                    coding subblock containing the sample q₀ and the                    absolute difference between the horizontal or                    vertical component of the two motion vectors used in                    the prediction of the two coding subblocks for the                    same reference picture is greater than or equal to 8                    in units of 1/16 luma samples.

                -   Two motion vectors for the same reference picture                    are used to predict the coding subblock containing                    the sample p₀, two motion vectors for the same                    reference picture are used to predict the coding                    subblock containing the sample q₀ and both of the                    following conditions are true:

                -    The absolute difference between the horizontal or                    vertical component of list 0 motion vectors used in                    the prediction of the two coding subblocks is                    greater than or equal to 8 in 1/16 luma samples, or                    the absolute difference between the horizontal or                    vertical component of the list 1 motion vectors used                    in the prediction of the two coding subblocks is                    greater than or equal to 8 in units of 1/16 luma                    samples.

                -    The absolute difference between the horizontal or                    vertical component of list 0 motion vector used in                    the prediction of the coding subblock containing the                    sample p₀ and the list 1 motion vector used in the                    prediction of the coding subblock containing the                    sample q₀ is greater than or equal to 8 in units of                    1/16 luma samples, or the absolute difference                    between the horizontal or vertical component of the                    list 1 motion vector used in the prediction of the                    coding subblock containing the sample p₀ and list 0                    motion vector used in the prediction of the coding                    subblock containing the sample q₀ is greater than or                    equal to 8 in units of 1/16 luma samples.

                -   Otherwise, the variable bS[xD_(i)][yD_(j)] is set                    equal to 0.

5.3. Embodiment #3 on Boundary Strength Derivation

8.8.3.6 Derivation process of boundary filtering strength

Inputs to this process are:

-   -   a picture sample array recPicture,    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,    -   a variable nCbW specifying the width of the current coding        block,    -   a variable nCbH specifying the height of the current coding        block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable cIdx specifying the colour component of the current        coding block,    -   a two-dimensional (nCbW)×(nCbH) array edgeFlags.        Output of this process is a two-dimensional (nCbW)×(nCbH) array        bS specifying the boundary filtering strength.        . . .        For xD_(i) with i=0 . . . xN and yD_(j) with j=0 . . . yN, the        following applies:    -   If edgeFlags[xD_(i)][yD_(j)] is equal to 0, the variable        bS[xD_(i)][yD_(j)] is set equal to 0.    -   Otherwise, the following applies:        -   . . .        -   The variable bS[xD_(i)][yD_(j)] is derived as follows:            -   If cIdx is equal to 0 and both samples p₀ and q₀ are in                a coding block with intra_bdpcm_flag equal to 1,                bS[xD_(i)][yD_(j)] is set equal to 0.            -   Otherwise, if the sample p₀ or q₀ is in the coding block                of a coding unit coded with intra prediction mode,                bS[xD_(i)][yD_(j)] is set equal to 2.            -   Otherwise, if the block edge is also a transform block                edge and the sample p₀ or q₀ is in a coding block with                ciip_flag equal to 1, bS[xD_(i)][yD_(j)] is set equal to                2.            -   Otherwise, if the block edge is also a transform block                edge and the sample p₀ or q₀ is in a transform block                which contains one or more non-zero transform                coefficient levels, bS[xD_(i)][yD_(j)] is set equal to                1.            -   Otherwise, if the block edge is also a transform block                edge, cIdx is greater than 0, and the sample p₀ or q₀ is                in a transform unit with tu_joint_cbcr_residual_flag                equal to 1, bS[xD_(i)][yD_(j)] is set equal to 1.            -   Otherwise, if the prediction mode of the coding subblock                containing the sample p₀ is different from the                prediction mode of the coding subblock containing the                sample q₀ (i.e. one of the coding subblock is coded in                IBC prediction mode and the other is coded in inter                prediction mode), bS[xD_(i)][yD_(j)] is set equal to 1.            -   Otherwise, if cIdx is equal to 0 and one or more of the                following conditions are true, bS[xD_(i)][yD_(j)] is set                equal to 1:                -   The coding subblock containing the sample p₀ and the                    coding subblock containing the sample q₀ are both                    coded in IBC prediction mode, and the absolute                    difference between the horizontal or vertical                    component of the block vectors used in the                    prediction of the two coding subblocks is greater                    than or equal to 8 in units of 1/16 luma samples.                -   For the prediction of the coding subblock containing                    the sample p₀ different reference pictures or a                    different number of motion vectors are used than for                    the prediction of the coding subblock containing the                    sample q₀.                -    NOTE 1—The determination of whether the reference                    pictures used for the two coding subblocks are the                    same or different is based only on which pictures                    are referenced, without regard to whether a                    prediction is formed using an index into reference                    picture list 0 or an index into reference picture                    list 1, and also without regard to whether the index                    position within a reference picture list is                    different.                -    NOTE 2—The number of motion vectors that are used                    for the prediction of a coding subblock with                    top-left sample covering (xSb, ySb), is equal to                    PredFlagL0[xSb][ySb]+PredFlagL1[xSb][ySb].                -   One motion vector is used to predict the coding                    subblock containing the sample p₀ and one motion                    vector is used to predict the coding subblock                    containing the sample q₀, and the absolute                    difference between the horizontal or vertical                    component of the motion vectors used is greater than                    or equal to 8 in units of 1/16 luma samples.                -   Two motion vectors and two different reference                    pictures are used to predict the coding subblock                    containing the sample p₀, two motion vectors for the                    same two reference pictures are used to predict the                    coding subblock containing the sample q₀ and the                    absolute difference between the horizontal or                    vertical component of the two motion vectors used in                    the prediction of the two coding subblocks for the                    same reference picture is greater than or equal to 8                    in units of 1/16 luma samples.                -   Two motion vectors for the same reference picture                    are used to predict the coding subblock containing                    the sample p₀, two motion vectors for the same                    reference picture are used to predict the coding                    subblock containing the sample q₀ and both of the                    following conditions are true:                -    The absolute difference between the horizontal or                    vertical component of list 0 motion vectors used in                    the prediction of the two coding subblocks is                    greater than or equal to 8 in 1/16 luma samples, or                    the absolute difference between the horizontal or                    vertical component of the list 1 motion vectors used                    in the prediction of the two coding subblocks is                    greater than or equal to 8 in units of 1/16 luma                    samples.                -    The absolute difference between the horizontal or                    vertical component of list 0 motion vector used in                    the prediction of the coding subblock containing the                    sample p₀ and the list 1 motion vector used in the                    prediction of the coding subblock containing the                    sample q₀ is greater than or equal to 8 in units of                    1/16 luma samples, or the absolute difference                    between the horizontal or vertical component of the                    list 1 motion vector used in the prediction of the                    coding subblock containing the sample p₀ and list 0                    motion vector used in the prediction of the coding                    subblock containing the sample q₀ is greater than or                    equal to 8 in units of 1/16 luma samples.            -   Otherwise, the variable bS[xD_(i)][yD_(j)] is set equal                to 0.

5.4. Embodiment #4 on Luma Deblocking Filtering Process

8.8.3.6.1 Decision Process for Luma Block Edges

Inputs to this process are:

-   -   a picture sample array recPicture,    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,    -   a location (xBl, yBl) specifying the top-left sample of the        current block relative to the top-left sample of the current        coding block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable bS specifying the boundary filtering strength,    -   a variable maxFilterLengthP specifying the max filter length,    -   a variable maxFilterLengthQ specifying the max filter length.        Outputs of this process are:    -   the variables dE, dEp and dEq containing decisions,    -   the modified filter length variables maxFilterLengthP and        maxFilterLengthQ,    -   the variable t_(C).        . . .        The following ordered steps apply:    -   . . .        -   1. When sidePisLargeBlk or sideQisLargeBlk is greater than            0, the following applies:            -   a. The variables dp0L, dp3L are derived and                maxFilterLengthP is modified as follows:                -   If sidePisLargeBlk is equal to 1, the following                    applies:                    dp0L=(dp0+Abs(p _(5,0)−2*p _(4,0) +p                    _(3,0))+1)>>1  (8-1087)                    dp3L=(dp3+Abs(p _(5,3)−2*p _(4,3) +p                    _(3,3))+1)>>1  (8-1088)                -   Otherwise, the following applies:                    dp0L=dp0  (8-1089)                    dp3L=dp3  (8-1090)                    maxFilterLengthP=3  (8-1091)            -   b. The variables dq0L and dq3L are derived as follows:                -   If sideQisLargeBlk is equal to 1, the following                    applies:                    dq0L=(dq0+Abs(q _(5,0)−2*q _(4,0) +q                    _(3,0))+1)>>1  (8-1092)                    dq3L=(dq3+Abs(q _(5,3)−2*q _(4,3) +q _(3,3))+1)>>1                      (8-1093)                -   Otherwise, the following applies:                    dq0L=dq0  (8-1094)                    dq3L=dq3  (8-1095)                -                -   . . .        -   2. The variables dE, dEp and dEq are derived as follows:            -   . . .

5.5. Embodiment #5 on Chroma Deblocking Filtering Process

8.8.3.6.3 Decision Process for Chroma Block Edges

This process is only invoked when ChromaArrayType is not equal to 0.

Inputs to this process are:

-   -   a chroma picture sample array recPicture,

    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,

    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,

    -   a variable cIdx specifying the colour component index,

    -   a variable cQpPicOffset specifying the picture-level chroma        quantization parameter offset,

    -   a variable bS specifying the boundary filtering strength,

    -   a variable maxFilterLengthCbCr.        Outputs of this process are

    -   the modified variable maxFilterLengthCbCr,

    -   the variable t_(C).        The variable maxK is derived as follows:

    -   If edgeType is equal to EDGE_VER, the following applies:        maxK=(SubHeightC==1)?3:1  (8-1124)

    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        maxK=(SubWidthC==1)?3:1  (8-1125)        The values p_(i) and q_(i) with i=0 . . . maxFilterLengthCbCr        and k=0 . . . maxK are derived as follows:

    -   If edgeType is equal to EDGE_VER, the following applies:        q _(i,k)=recPicture[xCb+xBl+i][yCb+yBl+k]  (8-1126)        p _(i,k)=recPicture[xCb+xBl−i−1][yCb+yBl+k]  (8-1127)        subSampleC=SubHeightC  (8-1128)

    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        q _(i,k)=recPicture[xCb+xBl+k][yCb+yBl+i]  (8-1129)        p _(i,k)=recPicture[xCb+xBl+k][yCb+yBl−i−1]  (8-1130)        subSampleC=SubWidthC  (8-1131)

    -   

    -                                           

    -                                                   The value of the variable β′ is determined as specified in Table        8-18 based on the quantization parameter Q derived as follows:        Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (8-1134)        where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth_(C)−8))  (8-1135)        The value of the variable t_(C)′ is determined as specified in        Table 8-18 based on the chroma quantization parameter Q derived        as follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (8-1136)        where slice_tc_offset_div2 is the value of the syntax element        slice_tc_offset_div2 for the slice that contains sample q_(0,0).        The variable t_(C) is derived as follows:        t _(C)=(BitDepth_(C)<10)?(t _(C)′+2)>>(10−BitDepth_(C)):t        _(C)′*(1<<(BitDepth_(C)−8))   (8-1137)        When maxFilterLengthCbCr is equal to 1 and bS is not equal to 2,        maxFilterLengthCbCr is set equal to 0.

5.6. Embodiment #6 on Chroma QP in Deblocking

8.8.3.6.3 Decision Process for Chroma Block Edges

This process is only invoked when ChromaArrayType is not equal to 0.

Inputs to this process are:

-   -   a chroma picture sample array recPicture,    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable cIdx specifying the colour component index,    -   a variable cQpPicOffset specifying the picture-level chroma        quantization parameter offset,    -   a variable bS specifying the boundary filtering strength,    -   a variable maxFilterLengthCbCr.        Outputs of this process are    -   the modified variable maxFilterLengthCbCr,    -   the variable t_(C).        The variable maxK is derived as follows:    -   If edgeType is equal to EDGE_VER, the following applies:        maxK=(SubHeightC==1)?3:1  (8-1124)    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        maxK=(SubWidthC==1)?3:1  (8-1125)        The values p_(i) and q_(i) with i=0 . . . maxFilterLengthCbCr        and k=0 . . . maxK are derived as follows:    -   If edgeType is equal to EDGE_VER, the following applies:        q _(i,k)=recPicture[xCb+xBl+i][yCb+yBl+k]  (8-1126)        p _(i,k)=recPicture[xCb+xBl−i−1][yCb+yBl+k]  (8-1127)        subSampleC=SubHeightC  (8-1128)    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        q _(i,k)=recPicture[xCb+xBl+k][yCb+yBl+i]  (8-1129)        p _(i,k)=recPicture[xCb+xBl+k][yCb+yBl−i−1]  (8-1130)        subSampleC=SubWidthC  (8-1131)        The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y)        values of the coding units which include the coding blocks        containing the sample q_(0,0) and p_(0,0), respectively.        The variable Qp_(C) is derived as follows:        qPi=Clip3(0,63,((Qp_(Q)+Qp_(P)+1)>>1)+cQpPicOffset)          (8-1132)        Qp_(C)=ChromaQpTable[cIdx−1][qPi]  (8-1133)        NOTE—The variable cQpPicOffset provides an adjustment for the        value of pps_cb_qp_offset or pps_cr_qp_offset, according to        whether the filtered chroma component is the Cb or Cr component.        However, to avoid the need to vary the amount of the adjustment        within the picture, the filtering process does not include an        adjustment for the value of slice_cb_qp_offset or        slice_cr_qp_offset nor (when cu_chroma_qp_offset_enabled_flag is        equal to 1) for the value of CuQpOffset_(Cb), CuQpOffset_(Cr),        or CuQpOffset_(CbCr).        . . .

5.7. Embodiment #7 on Chroma QP in Deblocking

8.8.3.6.3 Decision Process for Chroma Block Edges

This process is only invoked when ChromaArrayType is not equal to 0.

Inputs to this process are:

-   -   a chroma picture sample array recPicture,    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,    -   . . .        Outputs of this process are    -   the modified variable maxFilterLengthCbCr,    -   the variable t_(C).        The variable maxK is derived as follows:    -   If edgeType is equal to EDGE_VER, the following applies:        maxK=(SubHeightC==1)?3:1  (8-1124)    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        maxK=(SubWidthC==1)?3:1  (8-1125)        The values p_(i) and q_(i) with i=0 . . . maxFilterLengthCbCr        and k=0 . . . maxK are derived as follows:    -   If edgeType is equal to EDGE_VER, the following applies:        q _(i,k)=recPicture[xCb+xBl+i][yCb+yBl+k]  (8-1126)        p _(i,k)=recPicture[xCb+xBl−i−1][yCb+yBl+k]  (8-1127)        subSampleC=SubHeightC  (8-1128)    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        q _(i,k)=recPicture[xCb+xBl+k][yCb+yBl+i]  (8-1129)        p _(i,k)=recPicture[xCb+xBl+k][yCb+yBl−i−1]  (8-1130)        subSampleC=SubWidthC  (8-1131)        The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y)        values of the coding units which include the coding blocks        containing the sample q_(0,0) and p_(0,0), respectively.        .        The variable Qp_(C) is derived as follows:        qPi=Clip3(0,63,((Qp_(Q)+Qp_(P)+1)>>1)+cQpPicOffset)  (8-1132)        Qp_(C)=ChromaQpTable[cIdx−1][qPi]  (8-1133)    -   NOTE—The variable cQpPicOffset provides an adjustment for the        value of pps_cb_qp_offset or pps_cr_qp_offset, according to        whether the filtered chroma component is the Cb or Cr component.        However, to avoid the need to vary the amount of the adjustment        within the picture, the filtering process does not include an        adjustment for the value of slice_cb_qp_offset or        slice_cr_qp_offset nor (when cu_chroma_qp_offset_enabled_flag is        equal to 1) for the value of CuQpOffset_(Cb), CuQpOffset_(Cr),        or CuQpOffset_(CbCr).        The value of the variable β′ is determined as specified in Table        8-18 based on the quantization parameter Q derived as follows:        Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (8-1134)        where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth_(C)−8))  (8-1135)        The value of the variable t_(C)′ is determined as specified in        Table 8-18 based on the chroma quantization parameter Q derived        as follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (8-1136)        where slice_tc_offset_div2 is the value of the syntax element        slice_tc_offset_div2 for the slice that contains sample q_(0,0).

5.8. Embodiment #8 on Chroma QP in Deblocking

When making filter decisions for the depicted three samples (with solidcircles), the QPs of the luma CU that covers the center position of thechroma CU including the three samples is selected. Therefore, for the1^(st), 2^(nd), and 3^(rd) chroma sample (depicted in FIG. 11 ), onlythe QP of CU_(Y)3 is utilized, respectively.In this way, how to select luma CU for chromaquantization/dequantization process is aligned with that for chromafilter decision process.

5.9. Embodiment #9 on QP Used for JCCR Coded Blocks

8.7.3 Scaling Process for Transform Coefficients

Inputs to this process are:

-   -   a luma location (xTbY, yTbY) specifying the top-left sample of        the current luma transform block relative to the top-left luma        sample of the current picture,    -   a variable nTbW specifying the transform block width,    -   a variable nTbH specifying the transform block height,    -   a variable cIdx specifying the colour component of the current        block,    -   a variable bitDepth specifying the bit depth of the current        colour component.        Output of this process is the (nTbW)×(nTbH) array d of scaled        transform coefficients with elements d[x][y].        The quantization parameter qP is derived as follows:    -   If cIdx is equal to 0 and transform_skip_flag[xTbY][yTbY] is        equal to 0, the following applies:        qP=Qp′_(Y)  (8-950)    -   Otherwise, if cIdx is equal to 0 (and        transform_skip_flag[xTbY][yTbY] is equal to 1), the following        applies:        qP=Max(QpPrimeTsMin,Qp′_(Y))  (8-951)    -   Otherwise, if TuCResMode[xTbY][yTbY] is        , the following applies:        qP=Qp′_(CbCr)  (8-952)    -   Otherwise, if cIdx is equal to 1, the following applies:        qP=Qp′_(Cb)  (8-953)    -   Otherwise (cIdx is equal to 2), the following applies:        qP=Qp′Cr  (8-954)

5.10. Embodiment #10 on QP Used for JCCR Coded Blocks

8.8.3.2 Deblocking Filter Process for One Direction

Inputs to this process are:

-   -   the variable treeType specifying whether the luma        (DUAL_TREE_LUMA) or chroma components (DUAL_TREE_CHROMA) are        currently processed,

    -   when treeType is equal to DUAL_TREE_LUMA, the reconstructed        picture prior to deblocking i.e., the array recPicture_(L),

    -   when ChromaArrayType is not equal to 0 and treeType is equal to        DUAL_TREE_CHROMA, the arrays recPicture_(Cb) and        recPicture_(Cr),

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered.        Outputs of this process are the modified reconstructed picture        after deblocking, i.e:

    -   when treeType is equal to DUAL_TREE_LUMA, the array        recPicture_(L),

    -   when ChromaArrayType is not equal to 0 and treeType is equal to        DUAL_TREE_CHROMA, the arrays recPicture_(Cb) and        recPicture_(Cr).        The variables firstCompIdx and lastCompIdx are derived as        follows:        firstCompIdx=(treeType==DUAL_TREE_CHROMA)?1:0  (8-1022)        lastCompIdx=(treeType==DUAL_TREE_LUMA∥ChromaArrayType==0)?0:2          (8-1023)        For each coding unit and each coding block per colour component        of a coding unit indicated by the colour component index cIdx        ranging from firstCompIdx to lastCompIdx, inclusive, with coding        block width nCbW, coding block height nCbH and location of        top-left sample of the coding block (xCb, yCb), when cIdx is        equal to 0, or when cIdx is not equal to 0 and edgeType is equal        to EDGE_VER and xCb % 8 is equal 0, or when cIdx is not equal to        0 and edgeType is equal to EDGE_HOR and yCb % 8 is equal to 0,        the edges are filtered by the following ordered steps:        . . .        5. The picture sample array recPicture is derived as follows:

    -   If cIdx is equal to 0, recPicture is set equal to the        reconstructed luma picture sample array prior to deblocking        recPicture_(L).

    -   Otherwise, if cIdx is equal to 1, recPicture is set equal to the        reconstructed chroma picture sample array prior to deblocking        recPicture_(Cb).

    -   Otherwise (cIdx is equal to 2), recPicture is set equal to the        reconstructed chroma picture sample array prior to deblocking        recPicture_(Cr).        5.

    -   

    -   

    -   

    -   The edge filtering process for one direction is invoked for a        coding block as specified in clause 8.8.3.6 with the variable        edgeType, the variable cIdx, the reconstructed picture prior to        deblocking recPicture, the location (xCb, yCb), the coding block        width nCbW, the coding block height nCbH, and the arrays bS,        maxFilterLengthPs, and maxFilterLengthQs, as inputs, and the        modified reconstructed picture recPicture as output.        8.8.3.5 Derivation Process of Boundary Filtering Strength        Inputs to this process are:

    -   a picture sample array recPicture,

    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,

    -   a variable nCbW specifying the width of the current coding        block,

    -   a variable nCbH specifying the height of the current coding        block,

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,

    -   a variable cIdx specifying the colour component of the current        coding block,

    -   a two-dimensional (nCbW)×(nCbH) array edgeFlags.        Output of this process is a two-dimensional (nCbW)×(nCbH) array        bS specifying the boundary filtering strength.        The variables xD_(i), yD_(j), xN and yN are derived as follows:        . . .        For xD_(i) with i=0 . . . xN and yD_(j) with j=0 . . . yN, the        following applies:

    -   If edgeFlags[xD_(i)][yD_(j)] is equal to 0, the variable        bS[xD_(i)][yD_(j)] is set equal to 0.

    -   Otherwise, the following applies:        -   The sample values p₀ and q₀ are derived as follows:            -   If edgeType is equal to EDGE_VER, p₀ is set equal to                recPicture                [xCb+xD_(i)−1][yCb+yD_(j)] and q₀ is set equal to                recPicture                [xCb+xD_(i)][yCb+yD_(j)].            -   Otherwise (edgeType is equal to EDGE_HOR), p₀ is set                equal to recPicture                [xCb+xD_(i)][yCb+yD_(j)−1] and q₀ is set equal to                recPicture                [xCb+xD_(i)][yCb+yD_(j)].                . . .                8.8.3.6 Edge Filtering Process for One Direction                Inputs to this process are:

    -   a variable edgeType specifying whether vertical edges (EDGE_VER)        or horizontal edges (EDGE_HOR) are currently processed,

    -   a variable cIdx specifying the current colour component,

    -   the reconstructed picture prior to deblocking recPicture,

    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,

    -   a variable nCbW specifying the width of the current coding        block,

    -   a variable nCbH specifying the height of the current coding        block,

    -   the array bS specifying the boundary strength,

    -   the arrays maxFilterLengthPs and maxFilterLengthQs.        Output of this process is the modified reconstructed picture        after deblocking recPicture_(i).        . . .

    -   Otherwise (cIdx is not equal to 0), the filtering process for        edges in the chroma coding block of current coding unit        specified by cIdx consists of the following ordered steps:

    -   1. The variable cQpPicOffset is derived as follows:

    -   2.        .

    -   3. The decision process for Chroma block edges as specified in        clause 8.8.3.6.3 is invoked with the chroma picture sample array        recPicture, the location of the chroma coding block (xCb, yCb),        the location of the chroma block (xBl, yBl) set equal to        (xD_(k), yD_(m)), the edge direction edgeType, the variable        cIdx, the variable cQpPicOffset, the boundary filtering strength        bS[xD_(k)][yD_(m)], and the variable maxFilterLengthCbCr set        equal to maxFilterLengthPs[xD_(k)][yD_(m)] as inputs, and the        modified variable maxFilterLengthCbCr, and the variable t_(C) as        outputs.

    -   4. When maxFilterLengthCbCr is greater than 0, the filtering        process for chroma block edges as specified in clause 8.8.3.6.4        is invoked with the chroma picture sample array recPicture, the        location of the chroma coding block (xCb, yCb), the chroma        location of the block (xBl, yBl) set equal to (xD_(k), yD_(m)),        the edge direction edgeType, the variable maxFilterLengthCbC        , and the variable t_(C) as inputs, and the modified chroma        picture sample array recPicture as output.        -   .            8.8.3.6.3 Decision Process for Chroma Block Edges            This process is only invoked when ChromaArrayType is not            equal to 0.            Inputs to this process are:

    -   a chroma picture sample array recPicture,

    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,

    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,

    -   a variable cIdx specifying the colour component index,

    -   a variable cQpPicOffset specifying the picture-level chroma        quantization parameter offset,

    -   a variable bS specifying the boundary filtering strength,

    -   a variable maxFilterLengthCbCr.        Outputs of this process are

    -   the modified variable maxFilterLengthCbCr,

    -   the variable t_(C).        The variable maxK is derived as follows:

    -   If edgeType is equal to EDGE_VER, the following applies:        maxK=(SubHeightC==1)?3:1  (8-1124)

    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        maxK=(SubWidthC==1)?3:1  (8-1125)        The values p_(i) and q_(i) with        , i=0 . . . maxFilterLengthCbCr and k=0 . . . maxK are derived        as follows:

    -   If edgeType is equal to EDGE_VER, the following applies:        qc, _(i,k)=recPicture        [xCb+xBl+i][yCb+yBl+k]  (8-1126)        pc, _(i,k)=recPicture        [xCb+xBl−i−1][yCb+yBl+k]  (8-1127)        subSampleC=SubHeightC  (8-1128)

    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        q        _(i,k)=recPicture        [xCb+xBl+k][yCb+yBl+i]  (8-1129)        p        _(i,k)=recPicture        [xCb+xBl+k][yCb+yBl−i−1]  (8-1130)        subSampleC=SubWidthC  (8-1131)        The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y)        values of the coding units which include the coding blocks        containing the sample q_(0,0) and p_(0,0), respectively.        The variable Qp_(C) is derived as follows:        qPi=        (Qp_(Q)+Qp_(P)+1)>>1          (8-1132)                    

    -   NOTE—The variable cQpPicOffset provides an adjustment for the        value of pps_cb_qp_offset or pps_cr_qp_offset, according to        whether the filtered chroma component is the Cb or Cr component.        However, to avoid the need to vary the amount of the adjustment        within the picture, the filtering process does not include an        adjustment for the value of slice_cb_qp_offset or        slice_cr_qp_offset nor (when cu_chroma_qp_offset_enabled_flag is        equal to 1) for the value of CuQpOffset_(Cb), CuQpOffset_(Cr),        or CuQpOffset_(CbCr).        The value of the variable β′ is determined as specified in Table        8-18 based on the quantization parameter Q derived as follows:        Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (8-1134)        where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth_(C)−8))  (8-1135)        The value of the variable t_(C)′ is determined as specified in        Table 8-18 based on the chroma quantization parameter Q derived        as follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (8-1136)        where slice_tc_offset_div2 is the value of the syntax element        slice_tc_offset_div2 for the slice that contains sample q_(0,0).        The variable t_(C) is derived as follows:        t _(C)=(BitDepth_(C)<10)?(t _(C)′+2)>>(10−BitDepth_(C)):t        _(C)′*(1<<(BitDepth_(C)−8))   (8-1137)        When maxFilterLengthCbCr is equal to 1 and bS is not equal to 2,        maxFilterLengthCbCr is set equal to 0.        When maxFilterLengthCbCr is equal to 3, the following ordered        steps apply:

-   1. The variables n1, dpq0    , dpq1    , dp    , dq    and d    are derived as follows:    n1=(subSampleC==2)?1:3  (8-1138)    dp0    =Abs(p    _(2,0)−2*p    _(1,0) +p    _(0,0))  (8-1139)    dp1    =Abs(p    _(2,n1)−2*p    _(1,n1) +p    _(0,n1))  (8-1140)    dq0    =Abs(q    _(2,0)−2*q    _(1,0) +q    _(0,0))  (8-1141)    dq1    =Abs(q    _(2,n1)−2*q    _(1,n1) +q    _(0,n1))  (8-1142)    dpq0    =dp0    +dq0      (8-1143)    dpq1    =dp1    +dq1      (8-1144)    dp    =dp0    +dp1      (8-1145)    dq    =dq0    +dq1      (8-1146)    d    =dpq0    +dpq1      (8-1147)

-   2.

-   3. The variables dSam0 and dSam1 are both set equal to 0.

-   4. When d is less than 3, the following ordered steps apply:    -   a. The variable dpq is set equal to 2*dpq0.    -   b. The variable dSam0 is derived by invoking the decision        process for a chroma sample as specified in clause 8.8.3.6.8 for        the sample location (xCb+xBl, yCb+yBl) with sample values        p_(0,0), p_(3,0), q_(0,0), and q_(3,0), the variables dpq, p and        t_(C) as inputs, and the output is assigned to the decision        dSam0.    -   c. The variable dpq is set equal to 2*dpq1.    -   d. The variable dSam1 is modified as follows:        -   If edgeType is equal to EDGE_VER, for the sample location            (xCb+xBl, yCb+yBl+n1), the decision process for a chroma            sample as specified in clause 8.8.3.6.8 is invoked with            sample values p_(0,n1), p_(3,n1), g_(0,n1), and q_(3,n1),            the variables dpq, β and t_(C) as inputs, and the output is            assigned to the decision dSam1.        -   Otherwise (edgeType is equal to EDGE_HOR), f or the sample            location (xCb+xBl+n1, yCb+yBl), the decision process for a            chroma sample as specified in clause 8.8.3.6.8 is invoked            with sample values p_(0,n1), p_(3,n1), g_(0,n1) and            q_(3,n1), the variables dpq, β and t_(C) as inputs, and the            output is assigned to the decision dSam1.

-   5. The variable maxFilterLengthCbCr is modified as follows:    -   If dSam0 is equal to 1 and dSam1 is equal to 1,        maxFilterLengthCbCr is set equal to 3.    -   Otherwise, maxFilterLengthCbCr is set equal to 1.        8.8.3.6.4 Filtering Process for Chroma Block Edges        This process is only invoked when ChromaArrayType is not equal        to 0.        Inputs to this process are:    -   a chroma picture sample array recPicture,    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable maxFilterLengthCbCr containing the maximum chroma        filter length,

-   6.    -   the variable tC.        Output of this process is the modified chroma picture sample        array recPicture.        . . .        The values p_(i) and q_(i) with i=0 . . . maxFilterLengthCbCr        and k=0 . . . maxK are derived as follows:    -   If edgeType is equal to EDGE_VER, the following applies:        q _(i,k)=recPicture        [xCb+xBl+i][yCb+yBl+k]  (8-1150)        p _(i,k)=recPicture        [xCb+xBl−i−1][yCb+yBl+k]  (8-1151)    -   Otherwise (edgeType is equal to EDGE_HOR), the following        applies:        q _(i,k)=recPicture        [xCb+xBl+k][yCb+yBl+i]  (8-1152)        p _(i,k)=recPicture        [xCb+xBl+k][yCb+yBl−i−1]  (8-1153)        Depending on the value of edgeType, the following applies:    -   If edgeType is equal to EDGE_VER, for each sample location        (xCb+xBl, yCb+yBl+k), k=0 . . . maxK, the following ordered        steps apply:    -   1. The filtering process for a chroma sample as specified in        clause 8.8.3.6.9 is invoked with the variable        maxFilterLengthCbCr, the sample values p_(i,k), q_(i,k) with i=0        . . . maxFilterLengthCbCr, the locations (xCb+xBl−i−1,        yCb+yBl+k) and (xCb+xBl+i, yCb+yBl+k) with i=0 . . .        maxFilterLengthCbCr−1, and the variable t_(C) as inputs, and the        filtered sample values p_(i)′ and q_(i)′ with i=0 . . .        maxFilterLengthCbCr−1 as outputs.    -   2. The filtered sample values p₁′ and q₁′ with i=0 . . .        maxFilterLengthCbCr-1 replace the corresponding samples inside        the sample array recPicture as follows:        recPicture        [xCb+xBl+i][yCb+yBl+k]=q _(i)′  (8-1154)        recPicture        [xCb+xBl−i−1][yCb+yBl+k]=p _(i)′  (8-1155)    -   Otherwise (edgeType is equal to EDGE_HOR), for each sample        location (xCb+xBl+k, yCb+yBl), k=0 . . . maxK, the following        ordered steps apply:    -   1. The filtering process for a chroma sample as specified in        clause 8.8.3.6.9 is invoked with the variable        maxFilterLengthCbCr, the sample values p_(i,k), q_(i,k), with        i=0 . . . maxFilterLengthCbCr, the locations (xCb+xBl+k,        yCb+yBl−i−1) and (xCb+xBl+k, yCb+yBl+i), and the variable t_(C)        as inputs, and the filtered sample values p₁′ and q₁′ as        outputs.    -   2. The filtered sample values p₁′ and q₁′ replace the        corresponding samples inside the sample array recPicture as        follows:        recPicture        [xCb+xBl+k][yCb+yBl+i]=q _(i)′        recPicture        [xCb+xBl+k][yCb+yBl−i−1]=p _(i)′  (8-1156)

5.11. Embodiment #11

8.8.3.6.3 Decision Process for Chroma Block Edges

. . .

The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y) values ofthe coding units which include the coding blocks containing the sampleq_(0,0) and p_(0,0), respectively.

The variable Qp_(C) is derived as follows:qPi=Clip3(0,63,((Qp_(Q)+Qp_(P)+1)>>1)+cQpPicOffset)  (8-1132)Qp_(C)=ChromaQpTable[cIdx−1][qPi]  (8-1133)

-   -   

    -                                           

    -                                 

5.12 Embodiment #12

. . .

8.8.3.6.3 Decision Process for Chroma Block Edges

The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y) values ofthe coding units which include the coding blocks containing the sampleq_(0,0) and p_(0,0), respectively.

The variable Qp_(C) is derived as follows:qPi=Clip3(0,63,((Qp_(Q)+Qp_(P)+1)>>1)+cQpPicOffset)  (8-1132)Qp_(C)=ChromaQpTable[cIdx−1][qPi]  (8-1133)

-   -   NOTE—The variable cQpPicOffset provides an adjustment for the        value of pps_cb_qp_offset or pps_cr_qp_offset, according to        whether the filtered chroma component is the Cb or Cr component.        However, to avoid the need to vary the amount of the adjustment        within the picture, the filtering process does not include an        adjustment for the value of slice_cb_qp_offset or        slice_cr_qp_offset nor (when cu_chroma_qp_offset_enabled_flag is        equal to 1) for the value of CuQpOffset_(Cb), CuQpOffset_(Cr),        or CuQpOffset_(CbCr).        . . .

5.13 Embodiment #13

The embodiments are based on JVET-P2001-vE. The newly added texts aremarked by

font. The deleted texts are marked by bold underlined font.

Decision Process for Chroma Block Edges

This process is only invoked when ChromaArrayType is not equal to 0.

Inputs to this process are:

-   -   a chroma picture sample array recPicture,

    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,

    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,

    -   a variable cIdx specifying the colour component index,

    -   a variable bS specifying the boundary filtering strength,

    -   a variable maxFilterLengthP specifying the maximum filter        length,

    -   a variable maxFilterLengthQ specifying the maximum filter        length.        Outputs of this process are

    -   the modified filter length variables maxFilterLengthP and        maxFilterLengthQ,

    -   the variable t_(C).        . . .        The variable Qp_(P) is derived as follows:

    -   The luma location (xTb_(P), xTb_(P)) is set as the top-left luma        sample position of the transform block containing the sample        p_(0,0), relative to the top-left luma sample of the picture.

    -   If TuCResMode[xTb_(P)][yTb_(P)] is equal to 2, Qp_(P) is set        equal to Qp′_(CbCr) of the transform block containing the sample        p_(0,0).

    -   

    -   Otherwise, if cIdx is equal to 1        , Qp_(P) is set equal to Qp′_(Cb) of the transform block        containing the sample p_(0,0).

    -   Otherwise, Qp_(P) is set equal to Qp′_(Cr) of the transform        block containing the sample p_(0,0).

    -           The variable Qp_(Q) is derived as follows:

    -   The luma location (xTb_(Q), xTb_(Q)) is set as the top-left luma        sample position of the transform block containing the sample        q_(0,0), relative to the top-left luma sample of the picture.

    -   If TuCResMode[xTb_(Q)][yTb_(Q)] is equal to 2, Qp_(Q) is set        equal to Qp′_(CbCr) of the transform block containing the sample        q_(0,0).

    -   

    -   Otherwise, if cIdx is equal to 1        , Qp_(Q) is set equal to Qp′_(Cb) of the transform block        containing the sample q_(0,0).

    -   Otherwise, Qp_(Q) is set equal to Qp′_(Cr) of the transform        block containing the sample q_(0,0).

    -   

    -   The variable Qp_(C) is derived as follows:        Qp_(C)=(Qp_(Q)−QpBdOffset+Qp_(P)−QpBdOffset+1)>>1  (1321)

5.14 Embodiment #14

The embodiments are based on JVET-P2001-vE. The newly added texts aremarked by

font. The deleted texts are marked by bold underlined font.

Decision Process for Chroma Block Edges

This process is only invoked when ChromaArrayType is not equal to 0.

Inputs to this process are:

-   -   a chroma picture sample array recPicture,

    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,

    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,

    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,

    -   a variable cIdx specifying the colour component index,

    -   a variable bS specifying the boundary filtering strength,

    -   a variable maxFilterLengthP specifying the maximum filter        length,

    -   a variable maxFilterLengthQ specifying the maximum filter        length.        Outputs of this process are

    -   the modified filter length variables maxFilterLengthP and        maxFilterLengthQ,

    -   the variable t_(C).        . . .        The variable Qp_(P) is derived as follows:

    -   The luma location (xTb_(P), xTb_(P)) is set as the top-left luma        sample position of the transform block containing the sample        p_(0,0), relative to the top-left luma sample of the picture.

    -   If TuCResMode[xTb_(P)][yTb_(P)] is equal to 2, Qp_(P) is set        equal to Qp′_(CbCr) of the transform block containing the sample        p_(0,0).

    -   

    -   Otherwise, if cIdx is equal to 1        , Qp_(P) is set equal to Qp′_(Cb) of the transform block        containing the sample p_(0,0).

    -   Otherwise, Qp_(P) is set equal to Qp′_(Cr) of the transform        block containing the sample p_(0,0).

    -   

    -   The luma location (xTb_(Q), xTb_(Q)) is set as the top-left luma        sample position of the transform block containing the sample        q_(0,0), relative to the top-left luma sample of the picture.

    -   If TuCResMode[xTb_(Q)][yTb_(Q)] is equal to 2, Qp_(Q) is set        equal to Qp′_(CbCr) of the transform block containing the sample        q_(0,0).

    -   ,

    -   Otherwise, if cIdx is equal to 1        , Qp_(Q) is set equal to Qp′_(Cb) of the transform block        containing the sample q_(0,0).

    -   Otherwise, Qp_(Q) is set equal to Qp′_(Cr) of the transform        block containing the sample q_(0,0).

    -   .

The variable Qp_(C) is derived as follows:Qp_(C)=(Qp_(Q)−QpBdOffset+Qp_(P)−QpBdOffset+1)>>1  (1321). . .

5.15 Embodiment #15

The following FIG. 17 shows the proposed controlling logic.

7.3.2.6 Picture Header RBSP Syntax

if( !pic_dep_quant_enabled_flag)  sign_data_hiding_enabled_flag u(1) if(deblocking_filter_override_enabled_flag ) {  pic_deblocking_filter_override_present_flag u(1)   if(pic_deblocking_filter_override_present_flag) {   pic_deblocking_filter_override_flag u(1)    if(pic_deblocking_filter_override_flag ) {    pic_deblocking_filter_disabled_flag u(1)     if(!pic_deblocking_filter_disabled_flag) {      pic_beta_offset_div2 se(v)     pic_tc_offset_div2 se(v)     }    }   } } if( sps_lmcs_enabled_flag) {  pic_lmcs_enabled_flag u(1)7.3.7.1 General Slice Header Syntax

if(   deblocking_filter_override_enabled_flag    &&   !pic_deblocking_filter_override_present_flag) slice_deblocking_filter_override_flag u(1) if(slice_deblocking_filter_override_flag ) { slice_deblocking_filter_disabled_flag u(1)  if(!_slice_deblocking_filter_disabled_flag ) {  slice_beta_offset_div2se(v)  slice_tc_offset_div2 se(v)  } }

5.16 Embodiment #16

7.3.2.4 Picture Parameter Set RBSP Syntax

if( deblocking_filter_control_present_flag ) { deblocking_filter_override_enabled_flag u(1) pps_deblocking_filter_disabled_flag u(1)  if(!pps_deblocking_filter_disabled_flag ) {   pps_beta_offset_div2 se(v)  pps_tc_offset_div2 se(v)   pps_cb_beta_offset_div2 se(v)  pps_cb_tc_offset_div2 se(v)   pps_cr_beta_offset_div2 se(v)  pps_cr_tc_offset_div2 se(v) }7.3.2.6 Picture Header RBSP Syntax

if( pic_deblocking_filter_override_present_flag ) { pic_deblocking_filter_override_flag u(1)  if(pic_deblocking_filter_override_flag ) {  pic_deblocking_filter_disabled_flag u(1)   if(!pic_deblocking_filter_disabled_flag ) {    pic_beta_offset_div2 se(v)   pic_tc_offset_div2 se(v)    pic_cb_beta_offset_div2 se(v)   pic_cb_tc_offset_div2 se(v)    pic_cr_beta_offset_div2 se(v)   pic_cr_tc_offset_div2 se(v)   }  } }7.3.7.1 General slice header syntax

if( slice_deblocking_filter_override_flag ) { slice_deblocking_filter_disabled_flag u(1)  if(!slice_deblocking_filter_disabled_flag ) {  slice_beta_offset_div2 se(v) slice_tc_offset_div2 se(v)  slice_cb_beta_offset_div2 se(v) slice_cb_tc_offset_div2 se(v)  slice_cr_beta_offset_div2 se(v) slice_cr_tc_offset_div2 se(v)  } }7.4.3.4 Picture Parameter Set RBSP Semanticspps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the slice headers of the slices referringto the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2shall both be in the range of −6 to 6, inclusive. When not present, thevalue of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to beequal to 0.pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cr component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the slice headers of the slices referringto the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2shall both be in the range of −6 to 6, inclusive. When not present, thevalue of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to beequal to 0.7.4.3.6 Picture Headerpic_cb_beta_offset_div2 and pic_cb_tc_offset_div2 specify the deblockingparameter offsets for R and tC (divided by 2) that are applied to Cbcomponent for the slices associated with the PH. The values ofpic_beta_offset_div2 and pic tc_offset_div2 shall both be in the rangeof −6 to 6, inclusive. When not present, the values ofpic_beta_offset_div2 and pic_tc_offset_div2 are inferred to be equal topps_beta_offset_div2 and pps_tc_offset_div2, respectively.pic_cr_beta_offset_div2 and pic_cr_tc_offset_div2 specify the deblockingparameter offsets for R and t_(C) (divided by 2) that are applied to Crcomponent for the slices associated with the PH. The values ofpic_beta_offset_div2 and pic tc_offset_div2 shall both be in the rangeof −6 to 6, inclusive. When not present, the values ofpic_beta_offset_div2 and pic_tc_offset_div2 are inferred to be equal topps_beta_offset_div2 and pps_tc_offset_div2, respectively.7.4.8.1 General Slice Header Semanticsslice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive. When not present, the values ofslice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equalto pic_beta_offset_div2 and pic_tc_offset_div2, respectively.slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive. When not present, the values ofslice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equalto pic_beta_offset_div2 and pic_tc_offset_div2, respectively.8.8.3.6.3 Decision Process for Chroma Block Edges. . .The value of the variable β is determined as specified in Table 41 basedon the quantization parameter Q derived as follows:Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (1322)

-   -       -           where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth−8))  (1323)        The value of the variable t_(C)′ is determined as specified in        Table 41 based on the chroma quantization parameter Q derived as        follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (1324)    -       -           . . .

5.17 Embodiment #17

This embodiment is on top of embodiment #15.

7.3.2.4 Picture Parameter Set RBSP Syntax

if( deblocking_filter_control_present_flag ) { deblocking_filter_override_enabled_flag u(1) pps_deblocking_filter_disabled_flag u(1)  if(!pps_deblocking_filter_disabled_flag ) {   pps_beta_offset_div2 se(v)  pps_tc_offset_div2 se(v)   pps_cb_beta_offset_div2 se(v)  pps_cb_tc_offset_div2 se(v)   pps_cr_beta_offset_div2 se(v)  pps_cr_tc_offset_div2 se(v)  }7.3.7.1 General Slice Header Syntax

if( slice_deblocking_filter_override_flag ) { slice_deblocking_filter_disabled_flag u(1)  if(!slice_deblocking_filter_disabled_flag ) {   slice_beta_offset_div2se(v)   slice_tc_offset_div2 se(v)   slice_cb_beta_offset_div2 se(v)  slice_cb_tc_offset_div2 se(v)   slice_cr_beta_offset_div2 se(v)  slice_cr_tc_offset_div2 se(v)   }  }7.4.3.4 Picture Parameter Set RBSP Semanticspps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the slice headers of the slices referringto the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2shall both be in the range of −6 to 6, inclusive. When not present, thevalue of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to beequal to 0.pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cr component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the slice headers of the slices referringto the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2shall both be in the range of −6 to 6, inclusive. When not present, thevalue of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to beequal to 0.7.4.8.1 General Slice Header Semanticsslice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive. When not present, the values ofslice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equalto pps_beta_offset_div2 and pps_tc_offset_div2, respectively.slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive. When not present, the values ofslice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equalto pps_beta_offset_div2 and pps_tc_offset_div2, respectively.8.8.3.6.3 Decision Process for Chroma Block Edges. . .The value of the variable β′ is determined as specified in Table 41based on the quantization parameter Q derived as follows:Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (1322)

-   -       -           where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth−8))  (1323)        The value of the variable t_(C)′ is determined as specified in        Table 41 based on the chroma quantization parameter Q derived as        follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (1324)    -       -           . . .

5.18 Embodiment #18

This embodiment is based on embodiment #17.

7.4.3.4 Picture Parameter Set RBSP Semantics

pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current PPS. The values ofpps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the rangeof −6 to 6, inclusive. When not present, the value ofpps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to0.pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cr component for the current PPS. The values ofpps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the rangeof −6 to 6, inclusive. When not present, the value ofpps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to0.7.4.8.1 General Slice Header Semanticsslice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive.slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify thedeblocking parameter offsets for β and tC (divided by 2) that areapplied to Cb component for the current slice. The values ofslice_beta_offset_div2 and slice_tc_offset_div2 shall both be in therange of −6 to 6, inclusive.8.8.3.6.1 Decision Process for Luma Block Edges. . .The value of the variable β′ is determined as specified in Table 41based on the quantization parameter Q derived as follows:Q=Clip3(0,63,qP+(slice_beta_offset_div2<<1))  (1262)

where slice_beta_offset_div2 is the value of the syntax elementslice_beta_offset_div2 for the slice that contains sample q_(0,0).The variable β is derived as follows:β=β′*(1<<(BitDepth−8))  (1263)The value of the variable t_(C)′ is determined as specified in Table 41based on the quantization parameter Q derived as follows:Q=Clip3(0,65,qP+2*(bS−1)+(slice_tc_offset_div2<<1))  (1264)

  

. . .8.8.3.6.3 Decision Process for Chroma Block Edges. . .The value of the variable β is determined as specified in Table 41 basedon the quantization parameter Q derived as follows:Q=Clip3(0,63,Qp_(C)+(slice_beta_offset_div2<<1))  (1322)

-   -       -           where slice_beta_offset_div2 is the value of the syntax element        slice_beta_offset_div2 for the slice that contains sample        q_(0,0).        The variable β is derived as follows:        β=β′*(1<<(BitDepth−8))  (1323)        The value of the variable t_(C)′ is determined as specified in        Table 41 based on the chroma quantization parameter Q derived as        follows:        Q=Clip3(0,65,Qp_(C)+2*(bS−1)+(slice_tc_offset_div2<<1))  (1324)    -       -           . . .

5.19 Embodiment #19

This embodiment is related to the ACT.

intra_bdpcm_chroma_flag equal to 1 specifies that BDPCM is applied tothe current chroma coding blocks at the location (x0, y0), i.e. thetransform is skipped, the intra chroma prediction mode is specified byintra_bdpcm_chroma_dir_flag. intra_bdpcm_chroma_flag equal to 0specifies that BDPCM is not applied to the current chroma coding blocksat the location (x0, y0).When intra_bdpcm_chroma_flag is not present it is inferred to be equalto 0. it is inferred to be

The variable BdpcmFlag[x][y][cIdx] is set equal tointra_bdpcm_chroma_flag for x=x0 . . . x0+cbWidth−1, y=y0 . . .y0+cbHeight−1 and cIdx=1.2.intra_bdpcm_chroma_dir_flag equal to 0 specifies that the BDPCMprediction direction is horizontal. intra_bdpcm_chroma_dir_flag equal to1 specifies that the BDPCM prediction direction is vertical.

The variable BdpcmDir[x][y][cIdx] is set equal tointra_bdpcm_chroma_dir_flag for x=x0 . . . x0+cbWidth−1, y=y0 . . .y0+cbHeight−1 and cIdx=1.2.

5.1 Embodiment #20

This embodiment is related to the QP derivation for deblocking.

8.8.3.6.1 Decision Process for Luma Block Edges

Inputs to this process are:

-   -   a picture sample array recPicture,    -   a location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left sample of the        current picture,    -   a location (xBl, yBl) specifying the top-left sample of the        current block relative to the top-left sample of the current        coding block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable bS specifying the boundary filtering strength,    -   a variable maxFilterLengthP specifying the maximum filter        length,    -   a variable maxFilterLengthQ specifying the maximum filter        length.        Outputs of this process are:    -   the variables dE, dEp and dEq containing decisions,    -   the modified filter length variables maxFilterLengthP and        maxFilterLengthQ,    -   the variable t_(C).        . . .

The variables Qp_(Q) and Qp_(P) are set equal to the Qp_(Y) values ofthe coding units which include the coding blocks containing the sampleq_(0,0) and p_(0,0), respectively.

,

. . .8.8.3.6.3 Decision Process for Chroma Block EdgesThis process is only invoked when ChromaArrayType is not equal to 0.Inputs to this process are:

-   -   a chroma picture sample array recPicture,    -   a chroma location (xCb, yCb) specifying the top-left sample of        the current chroma coding block relative to the top-left chroma        sample of the current picture,    -   a chroma location (xBl, yBl) specifying the top-left sample of        the current chroma block relative to the top-left sample of the        current chroma coding block,    -   a variable edgeType specifying whether a vertical (EDGE_VER) or        a horizontal (EDGE_HOR) edge is filtered,    -   a variable cIdx specifying the colour component index,    -   a variable bS specifying the boundary filtering strength,    -   a variable maxFilterLengthP specifying the maximum filter        length,    -   a variable maxFilterLengthQ specifying the maximum filter        length.        Outputs of this process are    -   the modified filter length variables maxFilterLengthP and        maxFilterLengthQ,    -   the variable t_(C).        The variable Qp_(P) is derived as follows:    -   The luma location (xTb_(P), xTb_(P)) is set as the top-left luma        sample position of the transform block containing the sample        p_(0,0), relative to the top-left luma sample of the picture.    -   If TuCResMode[xTb_(P)][yTb_(P)] is equal to 2, Qp_(P) is set        equal to Qp′_(CbCr) of the transform block containing the sample        p_(0,0).    -   Otherwise, if cIdx is equal to 1, Qp_(P) is set equal to        Qp′_(Cb) of the transform block containing the sample p_(0,0).    -   Otherwise, Qp_(P) is set equal to Qp′_(Cr) of the transform        block containing the sample p_(0,0).        The variable Qp_(Q) is derived as follows:    -   The luma location (xTb_(Q), xTb_(Q)) is set as the top-left luma        sample position of the transform block containing the sample        q_(0,0), relative to the top-left luma sample of the picture.    -   If TuCResMode[xTb_(Q)][yTb_(Q)] is equal to 2, Qp_(Q) is set        equal to Qp′_(CbCr) of the transform block containing the sample        q_(0,0).    -   Otherwise, if cIdx is equal to 1, Qp_(Q) is set equal to        Qp′_(Cb) of the transform block containing the sample q_(0,0).    -   Otherwise, Qp_(Q) is set equal to Qp′_(Cr) of the transform        block containing the sample q_(0,0).        Qp_(C)=(Qp_(Q)−QpBdOffset+Qp_(P)−QpBdOffset+1)>>1  (1321)

6. Example Implementations of the Disclosed Technology

FIG. 12 is a block diagram of a video processing apparatus 1200. Theapparatus 1200 may be used to implement one or more of the methodsdescribed herein. The apparatus 1200 may be embodied in a smartphone,tablet, computer, Internet of Things (IoT) receiver, and so on. Theapparatus 1200 may include one or more processors 1202, one or morememories 1204 and video processing hardware 1206. The processor(s) 1202may be configured to implement one or more methods described in thepresent document. The memory (memories) 1204 may be used for storingdata and code used for implementing the methods and techniques describedherein. The video processing hardware 1206 may be used to implement, inhardware circuitry, some techniques described in the present document,and may be partly or completely be a part of the processors 1202 (e.g.,graphics processor core GPU or other signal processing circuitry).

In the present document, the term “video processing” may refer to videoencoding, video decoding, video compression or video decompression. Forexample, video compression algorithms may be applied during conversionfrom pixel representation of a video to a corresponding bitstreamrepresentation or vice versa. The bitstream representation of a currentvideo block may, for example, correspond to bits that are eitherco-located or spread in different places within the bitstream, as isdefined by the syntax. For example, a macroblock may be encoded in termsof transformed and coded error residual values and also using bits inheaders and other fields in the bitstream. Furthermore, duringconversion, a decoder may parse a bitstream with the knowledge that somefields may be present, or absent, based on the determination, as isdescribed in the above solutions. Similarly, an encoder may determinethat certain syntax fields are or are not to be included and generatethe bitstream representation accordingly by including or excluding thesyntax fields from the bitstream representation.

It will be appreciated that the disclosed methods and techniques willbenefit video encoder and/or decoder embodiments incorporated withinvideo processing devices such as smartphones, laptops, desktops, andsimilar devices by allowing the use of the techniques disclosed in thepresent document.

FIG. 13 is a flowchart for an example method 1300 of video processing.The method 1300 includes, at 1310, performing a conversion between avideo unit and a bitstream representation of the video unit, wherein,during the conversion, a deblocking filter is used on boundaries of thevideo unit such that when a chroma quantization parameter (QP) table isused to derive parameters of the deblocking filter, processing by thechroma QP table is performed on individual chroma QP values.

FIG. 18 is a block diagram that illustrates an example video codingsystem 100 that may utilize the techniques of this disclosure.

As shown in FIG. 18 , video coding system 100 may include a sourcedevice 110 and a destination device 120. Source device 110 generatesencoded video data which may be referred to as a video encoding device.Destination device 120 may decode the encoded video data generated bysource device 110 which may be referred to as a video decoding device.

Source device 110 may include a video source 112, a video encoder 114,and an input/output (I/O) interface 116.

Video source 112 may include a source such as a video capture device, aninterface to receive video data from a video content provider, and/or acomputer graphics system for generating video data, or a combination ofsuch sources. The video data may comprise one or more pictures. Videoencoder 114 encodes the video data from video source 112 to generate abitstream. The bitstream may include a sequence of bits that form abitstream representation of the video data. The bitstream may includecoded pictures and associated data. The coded picture is a bitstreamrepresentation of a picture. The associated data may include sequenceparameter sets, picture parameter sets, and other syntax structures. I/Ointerface 116 may include a modulator/demodulator (modem) and/or atransmitter. The encoded video data may be transmitted directly todestination device 120 via I/O interface 116 through network 130 a. Theencoded video data may also be stored onto a storage medium/server 130 bfor access by destination device 120.

Destination device 120 may include an I/O interface 126, a video decoder124, and a display device 122.

I/O interface 126 may include a receiver and/or a modem. I/O interface126 may acquire encoded video data from the source device 110 or thestorage medium/server 130 b. Video decoder 124 may decode the encodedvideo data. Display device 122 may display the decoded video data to auser. Display device 122 may be integrated with the destination device120, or may be external to destination device 120 which be configured tointerface with an external display device.

Video encoder 114 and video decoder 124 may operate according to a videocompression standard, such as the High Efficiency Video Coding (HEVC)standard, Versatile Video Coding (VVM) standard and other current and/orfurther standards.

FIG. 19 is a block diagram illustrating an example of video encoder 200,which may be video encoder 114 in the system 100 illustrated in FIG. 18.

Video encoder 200 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 19 , video encoder200 includes a plurality of functional components. The techniquesdescribed in this disclosure may be shared among the various componentsof video encoder 200. In some examples, a processor may be configured toperform any or all of the techniques described in this disclosure.

The functional components of video encoder 200 may include a partitionunit 201, a predication unit 202 which may include a mode select unit203, a motion estimation unit 204, a motion compensation unit 205 and anintra prediction unit 206, a residual generation unit 207, a transformunit 208, a quantization unit 209, an inverse quantization unit 210, aninverse transform unit 211, a reconstruction unit 212, a buffer 213, andan entropy encoding unit 214.

In other examples, video encoder 200 may include more, fewer, ordifferent functional components. In an example, predication unit 202 mayinclude an intra block copy (IBC) unit. The IBC unit may performpredication in an IBC mode in which at least one reference picture is apicture where the current video block is located.

Furthermore, some components, such as motion estimation unit 204 andmotion compensation unit 205 may be highly integrated, but arerepresented in the example of FIG. 19 separately for purposes ofexplanation.

Partition unit 201 may partition a picture into one or more videoblocks. Video encoder 200 and video decoder 300 may support variousvideo block sizes.

Mode select unit 203 may select one of the coding modes, intra or inter,e.g., based on error results, and provide the resulting intra- orinter-coded block to a residual generation unit 207 to generate residualblock data and to a reconstruction unit 212 to reconstruct the encodedblock for use as a reference picture. In some example, Mode select unit203 may select a combination of intra and inter predication (CIIP) modein which the predication is based on an inter predication signal and anintra predication signal. Mode select unit 203 may also select aresolution for a motion vector (e.g., a sub-pixel or integer pixelprecision) for the block in the case of inter-predication.

To perform inter prediction on a current video block, motion estimationunit 204 may generate motion information for the current video block bycomparing one or more reference frames from buffer 213 to the currentvideo block. Motion compensation unit 205 may determine a predictedvideo block for the current video block based on the motion informationand decoded samples of pictures from buffer 213 other than the pictureassociated with the current video block.

Motion estimation unit 204 and motion compensation unit 205 may performdifferent operations for a current video block, for example, dependingon whether the current video block is in an I slice, a P slice, or a Bslice.

In some examples, motion estimation unit 204 may perform uni-directionalprediction for the current video block, and motion estimation unit 204may search reference pictures of list 0 or list 1 for a reference videoblock for the current video block. Motion estimation unit 204 may thengenerate a reference index that indicates the reference picture in list0 or list 1 that contains the reference video block and a motion vectorthat indicates a spatial displacement between the current video blockand the reference video block. Motion estimation unit 204 may output thereference index, a prediction direction indicator, and the motion vectoras the motion information of the current video block. Motioncompensation unit 205 may generate the predicted video block of thecurrent block based on the reference video block indicated by the motioninformation of the current video block.

In other examples, motion estimation unit 204 may perform bi-directionalprediction for the current video block, motion estimation unit 204 maysearch the reference pictures in list 0 for a reference video block forthe current video block and may also search the reference pictures inlist 1 for another reference video block for the current video block.Motion estimation unit 204 may then generate reference indexes thatindicate the reference pictures in list 0 and list 1 containing thereference video blocks and motion vectors that indicate spatialdisplacements between the reference video blocks and the current videoblock. Motion estimation unit 204 may output the reference indexes andthe motion vectors of the current video block as the motion informationof the current video block. Motion compensation unit 205 may generatethe predicted video block of the current video block based on thereference video blocks indicated by the motion information of thecurrent video block.

In some examples, motion estimation unit 204 may output a full set ofmotion information for decoding processing of a decoder.

In some examples, motion estimation unit 204 may do not output a fullset of motion information for the current video. Rather, motionestimation unit 204 may signal the motion information of the currentvideo block with reference to the motion information of another videoblock. For example, motion estimation unit 204 may determine that themotion information of the current video block is sufficiently similar tothe motion information of a neighboring video block.

In one example, motion estimation unit 204 may indicate, in a syntaxstructure associated with the current video block, a value thatindicates to the video decoder 300 that the current video block has thesame motion information as the another video block.

In another example, motion estimation unit 204 may identify, in a syntaxstructure associated with the current video block, another video blockand a motion vector difference (VD). The motion vector differenceindicates a difference between the motion vector of the current videoblock and the motion vector of the indicated video block. The videodecoder 300 may use the motion vector of the indicated video block andthe motion vector difference to determine the motion vector of thecurrent video block.

As discussed above, video encoder 200 may predictively signal the motionvector. Two examples of predictive signaling techniques that may beimplemented by video encoder 200 include advanced motion vectorpredication (AMVP) and merge mode signaling.

Intra prediction unit 206 may perform intra prediction on the currentvideo block. When intra prediction unit 206 performs intra prediction onthe current video block, intra prediction unit 206 may generateprediction data for the current video block based on decoded samples ofother video blocks in the same picture. The prediction data for thecurrent video block may include a predicted video block and varioussyntax elements.

Residual generation unit 207 may generate residual data for the currentvideo block by subtracting (e.g., indicated by the minus sign) thepredicted video block(s) of the current video block from the currentvideo block. The residual data of the current video block may includeresidual video blocks that correspond to different sample components ofthe samples in the current video block.

In other examples, there may be no residual data for the current videoblock for the current video block, for example in a skip mode, andresidual generation unit 207 may not perform the subtracting operation.

Transform processing unit 208 may generate one or more transformcoefficient video blocks for the current video block by applying one ormore transforms to a residual video block associated with the currentvideo block.

After transform processing unit 208 generates a transform coefficientvideo block associated with the current video block, quantization unit209 may quantize the transform coefficient video block associated withthe current video block based on one or more quantization parameter (QP)values associated with the current video block.

Inverse quantization unit 210 and inverse transform unit 211 may applyinverse quantization and inverse transforms to the transform coefficientvideo block, respectively, to reconstruct a residual video block fromthe transform coefficient video block. Reconstruction unit 212 may addthe reconstructed residual video block to corresponding samples from oneor more predicted video blocks generated by the predication unit 202 toproduce a reconstructed video block associated with the current blockfor storage in the buffer 213.

After reconstruction unit 212 reconstructs the video block, loopfiltering operation may be performed reduce video blocking artifacts inthe video block.

Entropy encoding unit 214 may receive data from other functionalcomponents of the video encoder 200. When entropy encoding unit 214receives the data, entropy encoding unit 214 may perform one or moreentropy encoding operations to generate entropy encoded data and outputa bitstream that includes the entropy encoded data.

Some embodiments of the disclosed technology include making a decisionor determination to enable a video processing tool or mode. In anexample, when the video processing tool or mode is enabled, the encoderwill use or implement the tool or mode in the processing of a block ofvideo, but may not necessarily modify the resulting bitstream based onthe usage of the tool or mode. That is, a conversion from the block ofvideo to the bitstream representation of the video will use the videoprocessing tool or mode when itis enabled based on the decision ordetermination. In another example, when the video processing tool ormode is enabled, the decoder will process the bitstream with theknowledge that the bitstream has been modified based on the videoprocessing tool or mode. That is, a conversion from the bitstreamrepresentation of the video to the block of video will be performedusing the video processing tool or mode that was enabled based on thedecision or determination.

FIG. 20 is a block diagram illustrating an example of video decoder 300which may be video decoder 114 in the system 100 illustrated in FIG. 18.

The video decoder 300 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 20 , the videodecoder 300 includes a plurality of functional components. Thetechniques described in this disclosure may be shared among the variouscomponents of the video decoder 300. In some examples, a processor maybe configured to perform any or all of the techniques described in thisdisclosure.

In the example of FIG. 20 , video decoder 300 includes an entropydecoding unit 301, a motion compensation unit 302, an intra predictionunit 303, an inverse quantization unit 304, an inverse transformationunit 305, and a reconstruction unit 306 and a buffer 307. Video decoder300 may, in some examples, perform a decoding pass generally reciprocalto the encoding pass described with respect to video encoder 200 (FIG.19 ).

Entropy decoding unit 301 may retrieve an encoded bitstream. The encodedbitstream may include entropy coded video data (e.g., encoded blocks ofvideo data). Entropy decoding unit 301 may decode the entropy codedvideo data, and from the entropy decoded video data, motion compensationunit 302 may determine motion information including motion vectors,motion vector precision, reference picture list indexes, and othermotion information. Motion compensation unit 302 may, for example,determine such information by performing the AMVP and merge mode.

Motion compensation unit 302 may produce motion compensated blocks,possibly performing interpolation based on interpolation filters.Identifiers for interpolation filters to be used with sub-pixelprecision may be included in the syntax elements.

Motion compensation unit 302 may use interpolation filters as used byvideo encoder 20 during encoding of the video block to calculateinterpolated values for sub-integer pixels of a reference block. Motioncompensation unit 302 may determine the interpolation filters used byvideo encoder 200 according to received syntax information and use theinterpolation filters to produce predictive blocks.

Motion compensation unit 302 may uses some of the syntax information todetermine sizes of blocks used to encode frame(s) and/or slice(s) of theencoded video sequence, partition information that describes how eachmacroblock of a picture of the encoded video sequence is partitioned,modes indicating how each partition is encoded, one or more referenceframes (and reference frame lists) for each inter-encoded block, andother information to decode the encoded video sequence.

Intra prediction unit 303 may use intra prediction modes for examplereceived in the bitstream to form a prediction block from spatiallyadjacent blocks. Inverse quantization unit 303 inverse quantizes, i.e.,de-quantizes, the quantized video block coefficients provided in thebitstream and decoded by entropy decoding unit 301. Inverse transformunit 303 applies an inverse transform.

The reconstruction unit 306 may sum the residual blocks with thecorresponding prediction blocks generated by motion compensation unit202 or intra-prediction unit 303 to form decoded blocks. If desired, adeblocking filter may also be applied to filter the decoded blocks inorder to remove blockiness artifacts. The decoded video blocks are thenstored in buffer 307, which provides reference blocks for subsequentmotion compensation/intra predication and also produces decoded videofor presentation on a display device.

FIG. 21 is a block diagram showing an example video processing system1900 in which various techniques disclosed herein may be implemented.Various implementations may include some or all of the components of thesystem 1900. The system 1900 may include input 1902 for receiving videocontent. The video content may be received in a raw or uncompressedformat, e.g., 8 or 10 bit multi-component pixel values, or may be in acompressed or encoded format. The input 1902 may represent a networkinterface, a peripheral bus interface, or a storage interface. Examplesof network interface include wired interfaces such as Ethernet, passiveoptical network (PON), etc. and wireless interfaces such as Wi-Fi orcellular interfaces.

The system 1900 may include a coding component 1904 that may implementthe various coding or encoding methods described in the presentdocument. The coding component 1904 may reduce the average bitrate ofvideo from the input 1902 to the output of the coding component 1904 toproduce a bitstream representation of the video. The coding techniquesare therefore sometimes called video compression or video transcodingtechniques. The output of the coding component 1904 may be eitherstored, or transmitted via a communication connected, as represented bythe component 1906. The stored or communicated bitstream (or coded)representation of the video received at the input 1902 may be used bythe component 1908 for generating pixel values or displayable video thatis sent to a display interface 1910. The process of generatinguser-viewable video from the bitstream representation is sometimescalled video decompression. Furthermore, while certain video processingoperations are referred to as “coding” operations or tools, it will beappreciated that the coding tools or operations are used at an encoderand corresponding decoding tools or operations that reverse the resultsof the coding will be performed by a decoder.

Examples of a peripheral bus interface or a display interface mayinclude universal serial bus (USB) or high definition multimediainterface (HDMI) or Display port, and so on. Examples of storageinterfaces include SATA (serial advanced technology attachment), PCI,IDE interface, and the like. The techniques described in the presentdocument may be embodied in various electronic devices such as mobilephones, laptops, smartphones or other devices that are capable ofperforming digital data processing and/or video display.

FIG. 22 is a flowchart for example method 2200 of video processing.Operation 2202 includes performing a conversion between a video unit ofa video and a bitstream representation of the video, where theconversion includes applying a deblocking filter to at least somesamples on boundaries of the video unit, where deblocking quantizationparameter (QP) values used in the deblocking filter are determinedaccording to a rule, and where the rule specifies that whether thedeblocking QP values are equal to dequantization QP values for the videounit is based on whether an adaptive color transform (ACT) mode isapplied to the video unit.

In some embodiments of method 2200, when the ACT mode is applied to thevideo unit, a color space conversion is performed between residualvalues of the video unit and the video unit In some embodiments ofmethod 2200, the rule specifies that, in case that the ACT mode isapplied to the video unit, the deblocking QP values are based on QPvalues of the video unit prior to applying a QP adjustment according tothe ACT mode. In some embodiments of method 2200, the rule specifiesthat, in case the ACT mode is not applied to the video unit, thedeblocking QP values are equal to dequantization QP values. In someembodiments of method 2200, the rule specifies that, in case the ACTmode is not applied to the video unit and when a transform skip (TS)mode is not applied to the video unit, the deblocking QP values areequal to dequantization QP values.

FIG. 23 is a flowchart for example method 2300 of video processing.Operation 2302 includes performing a conversion between a video unit ofa video and a bitstream representation of the video according to a rule,where the rule specifies that an adaptive color transform (ACT) mode anda block-based delta pulse code modulation (BDPCM) coding tool areavailable for coding the video unit in a mutually exclusive manner.

In some embodiments of method 2300, when the ACT mode is applied to thevideo unit, a color space conversion is performed between residualvalues of the video unit and the video unit In some embodiments ofmethod 2300, when the BDPCM coding tool is applied to the video unit:quantized coefficients of the video unit are coded using sampledifferences during an encoding operation, or quantized coefficients aregenerated using the sample differences during a decoding operation. Insome embodiments of method 2300, the rule specifies that the BDPCMcoding tool is not applied to the video unit of a luma video componentwhen the ACT mode is applied to the video unit. In some embodiments ofmethod 2300, the rule specifies that the BDPCM coding tool is notapplied to the video unit of a chroma video component when the ACT modeis applied to the video unit. In some embodiments of method 2300, therule specifies that the BDPCM coding tool is not applied to the videounit of a luma video component or of a chroma video component when theACT mode is applied to the video unit. In some embodiments of method2300, the rule specifies that the ACT mode is not applied to the videounit when the BDPCM coding tool is applied to the video unit of a lumavideo component or of a chroma video component.

FIG. 24 is a flowchart for example method 2400 of video processing.Operation 2402 includes determining, for a conversion between a videounit of a video and a bitstream representation of the video, whether ablock differential pulse code modulation (BDPCM) coding tool is enabledfor the video unit based on whether an adaptive color transform (ACT)mode is enabled for the video unit. Operation 2404 includes performingthe conversion based on the determining.

In some embodiments of method 2400, when the ACT mode is enabled for thevideo unit, a color space conversion is performed between residualvalues of the video unit and the video unit In some embodiments ofmethod 2400, when the BDPCM coding tool is enabled for the video unit:samples of the video block are coded using sample differences withoutapplying a transform during an encoding operation, or samples of thevideo block are generated using sample differences without applying aninverse transform during a decoding operation. In some embodiments ofmethod 2400, the BDPCM coding tool for the video unit of a chroma videocomponent of the video is enabled in response to: the ACT mode beingenabled for the video block, the BDPCM coding tool being enabled foranother video unit of a luma video component of the video, and anindication in a sequence parameter set (SPS) that indicates that theBDPCM coding tool is enabled for the chroma video component of thevideo.

In some embodiments of method 2400, the BDPCM coding tool for the videounit of a chroma video component of the video is disabled in responseto: the ACT mode being disabled for the video block, or the BDPCM codingtool being disabled for another video unit of a luma video component ofthe video, or an indication in a sequence parameter set (SPS) thatindicates that the BDPCM coding tool is not enabled for the chroma videocomponent of the video. In some embodiments of method 2400, the BDPCMcoding tool for the video unit of a luma video component of the video isdisabled in response to: the ACT mode being enabled for the video block,an indication in a sequence parameter set (SPS) that indicates that theBDPCM coding tool is not enabled for the chroma video component of thevideo, and the bitstream representation not including a syntax elementthat indicates whether the BDPCM coding tool is enabled for the videounit of the luma video component. In some embodiments of method 2400,the ACT mode is not enabled for the video block in response to: theBDPCM coding tool for the video unit of a luma video component of thevideo being disabled, and an indication in a sequence parameter set(SPS) that indicates that the BDPCM coding tool is not enabled for thechroma video component of the video.

In some embodiments of method 2400, the BDPCM coding tool for the videounit of a luma video component of the video is disabled in response to:the ACT mode being enabled for the video block, and an indication in asequence parameter set (SPS) that indicates that the BDPCM coding toolis not enabled for the chroma video component of the video, wherein thebitstream representation does not include a syntax element thatindicates whether the BDPCM coding tool is enabled for the video unit ofthe luma video component. In some embodiments of methods 2200-2400, thevideo unit comprises a coding unit (CU), a prediction unit (PU), or atransform unit (TU). In some embodiments of methods 2200-2400, theperforming the conversion comprising encoding the video into thebitstream representation. In some embodiments of methods 2200-2400, theperforming the conversion comprises decoding the video from thebitstream representation. In some embodiments, a video decodingapparatus comprising a processor configured to implement techniques forembodiments related to methods 2200-2400. In some embodiments, a videoencoding apparatus comprising a processor configured to implementtechniques for embodiments related to methods 2200-2400. In someembodiments, a computer program product having computer instructionsstored thereon, the instructions, when executed by a processor, causesthe processor to implement techniques for embodiments related to methods2200-2400. In some embodiments, a computer readable medium that stores abitstream representation generated according to techniques forembodiments related to methods 2200-2400. In some embodiments, a videoprocessing apparatus for storing a bitstream representation, wherein thevideo processing apparatus is configured to implement techniques forembodiments related to methods 2200-2400.

Some preferred embodiments may be described using the followingclause-based format.

1. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that when a chroma quantizationparameter (QP) table is used to derive parameters of the deblockingfilter, processing by the chroma QP table is performed on individualchroma QP values.

2. The method of clause 1, wherein chroma QP offsets are added to theindividual chroma QP values subsequent to the processing by the chromaQP table.

3. The method of any of clauses 1-2, wherein the chroma QP offsets areadded to values outputted by the chroma QP table.

4. The method of any of clauses 1-2, wherein the chroma QP offsets arenot considered as input to the chroma QP table.

5. The method of clause 2, wherein the chroma QP offsets are at apicture-level or at a video unit-level.

6. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that chroma QP offsets are used in thedeblocking filter, wherein the chroma QP offsets are atpicture/slice/tile/brick/subpicture level.

7. The method of clause 6, wherein the chroma QP offsets used in thedeblocking filter are associated with a coding method applied on aboundary of the video unit.

8. The method of clause 7, wherein the coding method is a joint codingof chrominance residuals (JCCR) method.

9. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that chroma QP offsets are used in thedeblocking filter, wherein information pertaining to a same luma codingunit is used in the deblocking filter and for deriving a chroma QPoffset.

10. The method of clause 9, wherein the same luma coding unit covers acorresponding luma sample of a center position of the video unit,wherein the video unit is a chroma coding unit.

11. The method of clause 9, wherein a scaling process is applied to thevideo unit, and wherein one or more parameters of the deblocking filterdepend at least in part on quantization/dequantization parameters of thescaling process.

12. The method of clause 11, wherein the quantization/dequantizationparameters of the scaling process include the chroma QP offset.

13. The method of any of clauses 9-12, wherein the luma sample in thevideo unit is in the P side or Q side.

14. The method of clause 13, wherein the information pertaining to thesame luma coding unit depends on a relative position of the coding unitwith respect to the same luma coding unit.

15. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that chroma QP offsets are used in thedeblocking filter, wherein an indication of enabling usage of the chromaQP offsets is signaled in the bitstream representation.

16. The method of clause 15, wherein the indication is signaledconditionally in response to detecting one or more flags.

17. The method of clause 16, wherein the one or more flags are relatedto a JCCR enabling flag or a chroma QP offset enabling flag.

18. The method of clause 15, wherein the indication is signaled based ona derivation.

19. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that chroma QP offsets are used in thedeblocking filter, wherein the chroma QP offsets used in the deblockingfilter are identical of whether JCCR coding method is applied on aboundary of the video unit or a method different from the JCCR codingmethod is applied on the boundary of the video unit.

20. A method of video processing, comprising: performing a conversionbetween a video unit and a bitstream representation of the video unit,wherein, during the conversion, a deblocking filter is used onboundaries of the video unit such that chroma QP offsets are used in thedeblocking filter, wherein a boundary strength (BS) of the deblockingfilter is calculated without comparing reference pictures and/or anumber of motion vectors (MVs) associated with the video unit at a Pside boundary with reference pictures and/or a number of motion vectors(MVs) associated with the video unit at a Q side.

21. The method of clause 20, wherein the deblocking filter is disabledunder one or more conditions.

22. The method of clause 21, wherein the one or more conditions areassociated with: a magnitude of the motion vectors (MVs) or a thresholdvalue.

23. The method of clause 22, wherein the threshold value is associatedwith at least one of: i. contents of the video unit, ii. a messagesignaled in DPS/SPS/VPS/PPS/APS/picture header/slice header/tile groupheader/Largest coding unit (LCU)/Coding unit (CU)/LCU row/group ofLCUs/TU/PU block/Video coding unit, iii. a position ofCU/PU/TU/block/Video coding unit, iv. a coded mode of blocks withsamples along the boundaries, v. a transform matrix applied to the videounits with samples along the boundaries, vi. a shape or dimension of thevideo unit, vii. an indication of a color format, viii. a coding treestructure, ix. a slice/tile group type and/or picture type, x. a colorcomponent, xi. a temporal layer ID, or xii. a profile/level/tier of astandard.

24. The method of clause 20, wherein different QP offsets are used forTS coded video units and non-TS coded video units.

25. The method of clause 20, wherein a QP used in a luma filtering stepis related to a QP used in a scaling process of a luma block.

The items below are preferably implemented by some embodiments.Additional features are shown in the listing in the previous section,e.g., items 31-32.

26. A method of video processing, comprising: determining, for aconversion between a video unit of a component of a video and abitstream representation of the video, a size of a quantization groupfor the video unit, based on a constraint rule that specifies that thesize must be larger than K, where K is a positive number; and performingthe conversion based on the determining.

27. The method of clause 26, wherein the component is a chroma componentand K=4.

28. The method of clause 26, wherein the component is a luma componentand K=8.

29. The method of any of clauses 1-28, wherein the conversion comprisesencoding the video into the bitstream representation.

30. The method of any of clauses 1-28, wherein the conversion comprisesparsing and decoding the bitstream representation to generate the video.

31. A video decoding apparatus comprising a processor configured toimplement a method recited in one or more of clauses 1 to 30.

32. A video encoding apparatus comprising a processor configured toimplement a method recited in one or more of clauses 1 to 30.

In some embodiments, the following technical solutions may be preferablyimplemented.

1. A method of video processing (e.g., method 2200 depicted in FIG. 22), comprising: performing (2202) a conversion between a video unit of avideo and a bitstream of the video, wherein the conversion includesapplying a deblocking filter to at least some samples on boundaries ofthe video unit, wherein deblocking quantization parameter (QP) valuesused in the deblocking filter are determined according to a rule, andwherein the rule specifies that whether the deblocking QP values areequal to dequantization QP values for the video unit is based on whetheran adaptive color transform (ACT) mode is applied to the video unit.

2. The method of solution 1, wherein when the ACT mode is applied to thevideo unit, a color space conversion is performed between residualvalues of the video unit and the video unit.

3. The method of solution 1, wherein the rule specifies that, in casethat the ACT mode is applied to the video unit, the deblocking QP valuesare based on QP values of the video unit prior to applying a QPadjustment according to the ACT mode.

4. The method of solution 1, wherein the rule specifies that, in casethe ACT mode is not applied to the video unit, the deblocking QP valuesare equal to dequantization QP values.

5. The method of solution 1, wherein the rule specifies that, in casethe ACT mode is not applied to the video unit and when a transform skip(TS) mode is not applied to the video unit, the deblocking QP values areequal to dequantization QP values.

6. A method of video processing (e.g., method 2300 depicted in FIG. 23), comprising: performing (2302) a conversion between a video unit of avideo and a bitstream of the video according to a rule, wherein the rulespecifies that an adaptive color transform (ACT) mode and a block-baseddelta pulse code modulation (BDPCM) coding tool are available for codingthe video unit in a mutually exclusive manner.

7. The method of solution 6, wherein when the ACT mode is applied to thevideo unit, a color space conversion is performed between residualvalues of the video unit and the video unit.

8. The method of solution 6, wherein when the BDPCM coding tool isapplied to the video unit: quantized coefficients of the video unit arecoded using sample differences during an encoding operation, orquantized coefficients are generated using the sample differences duringa decoding operation.

9. The method of solution 6, wherein the rule specifies that the BDPCMcoding tool is not applied to the video unit of a luma video componentwhen the ACT mode is applied to the video unit.

10. The method of solution 6, wherein the rule specifies that the BDPCMcoding tool is not applied to the video unit of a chroma video componentwhen the ACT mode is applied to the video unit.

11. The method of solution 6, wherein the rule specifies that the BDPCMcoding tool is not applied to the video unit of a luma video componentor of a chroma video component when the ACT mode is applied to the videounit.

12. The method of solution 6, wherein the rule specifies that the ACTmode is not applied to the video unit when the BDPCM coding tool isapplied to the video unit of a luma video component or of a chroma videocomponent.

13. A method of video processing (e.g., method 2400 depicted in FIG. 24), comprising: determining (2402), for a conversion between a video unitof a video and a bitstream of the video, whether a block differentialpulse code modulation (BDPCM) coding tool is enabled for the video unitbased on whether an adaptive color transform (ACT) mode is enabled forthe video unit; and performing (2404) the conversion based on thedetermining.

14. The method of solution 13, wherein when the ACT mode is enabled forthe video unit, a color space conversion is performed between residualvalues of the video unit and the video unit.

15. The method of solution 13, wherein when the BDPCM coding tool isenabled for the video unit: samples of the video block are coded usingsample differences without applying a transform during an encodingoperation, or samples of the video block are generated using sampledifferences without applying an inverse transform during a decodingoperation.

16. The method of solution 13, wherein the BDPCM coding tool for thevideo unit of a chroma video component of the video is enabled inresponse to: the ACT mode being enabled for the video block, the BDPCMcoding tool being enabled for another video unit of a luma videocomponent of the video, and an indication in a sequence parameter set(SPS) that indicates that the BDPCM coding tool is enabled for thechroma video component of the video.

17. The method of solution 13, wherein the BDPCM coding tool for thevideo unit of a chroma video component of the video is disabled inresponse to: the ACT mode being disabled for the video block, or theBDPCM coding tool being disabled for another video unit of a luma videocomponent of the video, or an indication in a sequence parameter set(SPS) that indicates that the BDPCM coding tool is not enabled for thechroma video component of the video.

18. The method of solution 13, wherein the BDPCM coding tool for thevideo unit of a luma video component of the video is disabled inresponse to: the ACT mode being enabled for the video block, anindication in a sequence parameter set (SPS) that indicates that theBDPCM coding tool is not enabled for the chroma video component of thevideo, and the bitstream not including a syntax element that indicateswhether the BDPCM coding tool is enabled for the video unit of the lumavideo component.

19. The method of solution 13, wherein the ACT mode is not enabled forthe video block in response to: the BDPCM coding tool for the video unitof a luma video component of the video being disabled, and an indicationin a sequence parameter set (SPS) that indicates that the BDPCM codingtool is not enabled for the chroma video component of the video.

20. The method of solution 13, wherein the BDPCM coding tool for thevideo unit of a luma video component of the video is disabled inresponse to: the ACT mode being enabled for the video block, and anindication in a sequence parameter set (SPS) that indicates that theBDPCM coding tool is not enabled for the chroma video component of thevideo, wherein the bitstream does not include a syntax element thatindicates whether the BDPCM coding tool is enabled for the video unit ofthe luma video component.

21. The method of any of solutions 1 to 20, wherein the video unitcomprises a coding unit (CU), a prediction unit (PU), or a transformunit (TU).

22. The method of any of solutions 1 to 21, wherein the performing theconversion comprising encoding the video into the bitstream.

23. The method of any of solutions 1 to 21, wherein the performing theconversion comprises decoding the video from the bitstream.

24. The method of any of solutions 1 to 21, wherein the performing theconversion comprises encoding the video into the bitstreamrepresentation; and the method further comprises storing the bitstreamin a non-transitory computer-readable recording medium.

25. A method for storing bitstream of a video, comprising: generating abitstream of a video from a video unit of the video, and storing thebitstream in a non-transitory computer-readable recording medium;wherein the generating the bitstream includes applying a deblockingfilter to at least some samples on boundaries of the video unit, whereindeblocking quantization parameter (QP) values used in the deblockingfilter are determined according to a rule, and wherein the rulespecifies that whether the deblocking QP values are equal todequantization QP values for the video unit is based on whether anadaptive color transform (ACT) mode is applied to the video unit.

26. A video decoding apparatus comprising a processor configured toimplement a method recited in one or more of solutions 1 to 23.

27. A video encoding apparatus comprising a processor configured toimplement a method recited in one or more of solutions 1 to 25.

28. A computer program product having computer instructions storedthereon, the instructions, when executed by a processor, causes theprocessor to implement a method recited in any of solutions 1 to 25.

29. A non-transitory computer-readable storage medium that stores abitstream generated according to the method in any one of solutions 1 to23.

30. A non-transitory computer-readable storage medium storinginstructions that cause a processor to implement a method recited in anyof solutions 1 to 25.

31. A video processing apparatus for storing a bitstream, wherein thevideo processing apparatus is configured to implement a method recitedin any one or more of solutions 1 to 25.

The disclosed and other solutions, examples, embodiments, modules andthe functional operations described in this document can be implementedin digital electronic circuitry, or in computer software, firmware, orhardware, including the structures disclosed in this document and theirstructural equivalents, or in combinations of one or more of them. Thedisclosed and other embodiments can be implemented as one or morecomputer program products, i.e., one or more modules of computer programinstructions encoded on a computer readable medium for execution by, orto control the operation of, data processing apparatus. The computerreadable medium can be a machine-readable storage device, amachine-readable storage substrate, a memory device, a composition ofmatter effecting a machine-readable propagated signal, or a combinationof one or more them. The term “data processing apparatus” encompassesall apparatus, devices, and machines for processing data, including byway of example a programmable processor, a computer, or multipleprocessors or computers. The apparatus can include, in addition tohardware, code that creates an execution environment for the computerprogram in question, e.g., code that constitutes processor firmware, aprotocol stack, a database management system, an operating system, or acombination of one or more of them. A propagated signal is anartificially generated signal, e.g., a machine-generated electrical,optical, or electromagnetic signal, that is generated to encodeinformation for transmission to suitable receiver apparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located atone site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this document can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random-access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Computer readable media suitable for storingcomputer program instructions and data include all forms of non-volatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto optical disks; and CD ROM and DVD-ROM disks. The processor andthe memory can be supplemented by, or incorporated in, special purposelogic circuitry.

While this patent document contains many specifics, these should not beconstrued as limitations on the scope of any subject matter or of whatmay be claimed, but rather as descriptions of features that may bespecific to particular embodiments of particular techniques. Certainfeatures that are described in this patent document in the context ofseparate embodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Moreover, the separation of various system components in theembodiments described in this patent document should not be understoodas requiring such separation in all embodiments.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this patent document.

What is claimed is:
 1. A method of video processing, comprising:applying, during a conversion between a video unit of a video and abitstream of the video, a deblocking filter to at least some samples onboundaries of the video unit, wherein deblocking quantization parameter(QP) values used in the deblocking filter are determined according to arule; and performing the conversion based on the deblocking QP values,wherein the rule specifies that a relationship between the deblocking QPvalues and dequantization QP values used in a quantization ordequantization process for the video unit is based on whether anadaptive color transform mode is applied to the video unit, wherein inthe adaptive color transform mode, for an encoding operation, visualsignals are converted from a first color domain to a second colordomain, or for a decoding operation, the visual signals are convertedfrom the second color domain to the first color domain, wherein thevideo unit is a chroma coding block, and the rule specifies that adifferential coding tool is not applied to the chroma coding block whenthe adaptive color transform mode is applied to the chroma coding block,and wherein in a differential coding mode, residuals of samples of thechroma coding block are represented in the bitstream using differencesbetween quantized residuals and predictors of the quantized residuals.2. The method of claim 1, wherein the rule specifies that, in case thatthe adaptive color transform mode is applied to the video unit, thedeblocking QP values are derived based on QP values prior to applying aQP adjustment according to the adaptive color transform mode and thedequantization QP values are QP values which applied the QP adjustment.3. The method of claim 1, wherein the rule specifies that, in case thatthe adaptive color transform mode is not applied to the video unit, thedeblocking QP values are derived based on the dequantization QP valuesfor the video unit.
 4. The method of claim 3, wherein the rule specifiesthat, in case that the adaptive color transform mode is not applied tothe video unit, the deblocking QP values are equal to the dequantizationQP values for the video unit.
 5. The method of claim 1, wherein the rulespecifies that, in case that both the adaptive color transform mode anda transform skip (TS) mode are not applied to the video unit, thedeblocking QP values are derived based on the dequantization QP valuesfor the video unit.
 6. The method of claim 5, wherein the rule specifiesthat, in case that both the adaptive color transform mode and the TSmode is not applied to the video unit, the deblocking QP values areequal to the dequantization QP values for the video unit.
 7. The methodof claim 1, wherein the differences are represented using a block baseddifferential pulse coding modulation representation.
 8. The method ofclaim 1, wherein the conversion includes encoding the video into thebitstream.
 9. The method of claim 1, wherein the conversion includesdecoding the video from the bitstream.
 10. An apparatus for processingvideo data comprising: a processor; and a non-transitory memory withinstructions thereon, wherein the instructions upon execution by theprocessor, cause the processor to: apply, during a conversion between avideo unit of a video and a bitstream of the video, a deblocking filterto at least some samples on boundaries of the video unit, whereindeblocking quantization parameter (QP) values used in the deblockingfilter are determined according to a rule; and perform the conversionbased on the deblocking QP values, wherein the rule specifies that arelationship between the deblocking QP values and dequantization QPvalues used in a quantization or dequantization process for the videounit is based on whether an adaptive color transform mode is applied tothe video unit, wherein in the adaptive color transform mode, for anencoding operation, visual signals are converted from a first colordomain to a second color domain, or for a decoding operation, the visualsignals are converted from the second color domain to the first colordomain, wherein the video unit is a chroma coding block, and the rulespecifies that a differential coding tool is not applied to the chromacoding block when the adaptive color transform mode is applied to thechroma coding block, and wherein in a differential coding mode,residuals of samples of the chroma coding block are represented in thebitstream using differences between quantized residuals and predictorsof the quantized residuals.
 11. The apparatus of claim 10, wherein therule specifies that: in case that the adaptive color transform mode isapplied to the video unit, the deblocking QP values are derived based onQP values prior to applying a QP adjustment according to the adaptivecolor transform mode and the dequantization QP values are QP valueswhich applied the QP adjustment; in case that the adaptive colortransform mode is not applied to the video unit, the deblocking QPvalues are derived based on the dequantization QP values for the videounit; or in case that both the adaptive color transform mode and atransform skip (TS) mode are not applied to the video unit, thedeblocking QP values are derived based on the dequantization QP valuesfor the video unit.
 12. The apparatus of claim 10, wherein thedifferences are represented using a block based differential pulsecoding modulation representation.
 13. A non-transitory computer-readablestorage medium storing instructions that cause a processor to: apply,during a conversion between a video unit of a video and a bitstream ofthe video, a deblocking filter to at least some samples on boundaries ofthe video unit, wherein deblocking quantization parameter (QP) valuesused in the deblocking filter are determined according to a rule; andperform the conversion based on the deblocking QP values, wherein therule specifies that a relationship between the deblocking QP values anddequantization QP values used in a quantization or dequantizationprocess for the video unit is based on whether an adaptive colortransform mode is applied to the video unit, wherein in the adaptivecolor transform mode, for an encoding operation, visual signals areconverted from a first color domain to a second color domain, or for adecoding operation, the visual signals are converted from the secondcolor domain to the first color domain, wherein the video unit is achroma coding block, and the rule specifies that a differential codingtool is not applied to the chroma coding block when the adaptive colortransform mode is applied to the chroma coding block, and wherein in adifferential coding mode, residuals of samples of the chroma codingblock are represented in the bitstream using differences betweenquantized residuals and predictors of the quantized residuals.
 14. Thenon-transitory computer-readable storage medium of claim 13, wherein therule specifies that: in case that the adaptive color transform mode isapplied to the video unit, the deblocking QP values are derived based onQP values prior to applying a QP adjustment according to the adaptivecolor transform mode and the dequantization QP values are QP valueswhich applied the QP adjustment; in case that the adaptive colortransform mode is not applied to the video unit, the deblocking QPvalues are derived based on the dequantization QP values for the videounit; or in case that both the adaptive color transform mode and atransform skip (TS) mode are not applied to the video unit, thedeblocking QP values are derived based on the dequantization QP valuesfor the video unit.
 15. The non-transitory computer-readable storagemedium of claim 13, wherein the differences are represented using ablock based differential pulse coding modulation representation.
 16. Anon-transitory computer-readable recording medium storing a bitstream ofa video which is generated by a method performed by a video processingapparatus, wherein the method comprises: applying a deblocking filter toat least some samples on boundaries of a video unit of the video,wherein deblocking quantization parameter (QP) values used in thedeblocking filter are determined according to a rule; and generating thebitstream based on the deblocking QP values, wherein the rule specifiesthat a relationship between the deblocking QP values and dequantizationQP values used in a quantization or dequantization process for the videounit is based on whether an adaptive color transform mode is applied tothe video unit, wherein in the adaptive color transform mode, for anencoding operation, visual signals are converted from a first colordomain to a second color domain, or for a decoding operation, the visualsignals are converted from the second color domain to the first colordomain, wherein the video unit is a chroma coding block, and the rulespecifies that a differential coding tool is not applied to the chromacoding block when the adaptive color transform mode is applied to thechroma coding block, and wherein in a differential coding mode,residuals of samples of the chroma coding block are represented in thebitstream using differences between quantized residuals and predictorsof the quantized residuals.
 17. The non-transitory computer-readablerecording medium of claim 16, wherein the rule specifies that: in casethat the adaptive color transform mode is applied to the video unit, thedeblocking QP values are derived based on QP values prior to applying aQP adjustment according to the adaptive color transform mode and thedequantization QP values are QP values which applied the QP adjustment;in case that the adaptive color transform mode is not applied to thevideo unit, the deblocking QP values are derived based on thedequantization QP values for the video unit; or in case that both theadaptive color transform mode and a transform skip (TS) mode are notapplied to the video unit, the deblocking QP values are derived based onthe dequantization QP values for the video unit.
 18. The non-transitorycomputer-readable recording medium of claim 16, wherein the differencesare represented using a block based differential pulse coding.